Grandparents

I wouldn't worry about the bond with DS just yet. How often a 7m old sees a person makes no difference to the long term bond
Focus on your own relationship with your mother and give some thought to what you want that to look like, and if it's achievable. How much are you prepared to compromise and will the benefit to you be worth it? There's a balance between tolerating people's difficult ways and letting them ride rough shod over you, and you need to decide where that lies.
You may decide the relationship is good enough overall to go to her. You may decide this is just the latest in a history of her calling the shots then manipulating you with sulks. Work that out first.

She's stopped talking to you? Eww. I really hate that childish behaviour. Grow up. It doesn't matter that it's worded as her not wanting contact at the moment, it's still a playground tactic. (That I also hated as a child and would avoid friendships with anyone who did this.)

You're not being unreasonable to suggest it's 50/50 you to her and her to you. It's hard travelling with a little one, they need changing and entertaining and so much stuff! And it's expensive at a time when your income's likely to be lower.

Please don't feel guilty. Rise above. Approach with grace. You're offering her an opportunity to have a good relationship and it's her responsibility to pull her weight and not be a little princess on her throne waiting for people to come to her. It's sad that he's not seeing her but that's not your fault, it's your mother's choice to be inflexible and uncollaborative.

Be clear about your boundaries. "I can afford to come down once a month"
Put a positive spin on it "I want you to see him in his usual environment, he wants to show you his favourite park / farm / beach"

You're a mum. You're his mum. You can't be bullied by your own mum any more.

Hang on, I've just re-read your post and not sure I've understood how often she's expecting you to go to her?!

It’s just pure laziness. She’s been used to everyone visiting her I bet, it’s too much of an effort for her

She just can’t be asked to put the effort in and expects you to do the journey because you have been doing it in the past. It’s out of order for your mum to expect you to lug your 7 month old on 2 trains 1 hour 40 mins every time to go visit her. She is more upset that she isn’t getting her own way than missing out on you and your son.

I think it is so sad when someone takes an impossible stance. She seems to have a history of this. Not wanting to travel anywhere is a pain in the arse . And there is not a legitimate reason for it . Nothing you can do but try not to blame yourself. It is all on her.

She sounds super unreasonable and difficult and your partners behaviour and opinion towards her speaks volumes.

It sounds like you’re used to her being this way and you having to bend over backwards to please her but you have a child now and you need to stop.

She doesn’t work, she doesn’t have a disability which makes travel difficult, she has no reason not to travel to you.

Stand your ground otherwise she’ll just continue to walk all over you.

I’m “super judgemental” of @Loulou2980 ‘s mother on the basis of the information in this thread

Does your DH make your mother feel unwelcome?. You said that he's super judgemental about her.

The only one being unreasonable here is your mum. If she wants to see you and your child she needs to make the effort to travel as much as you (or more, because you have to make the journey with a baby).
Don’t let her manipulate you, stand your ground and say no.

But why do you want someone to be around you or your child who behaves like this?

This behaviour won’t even have come out of the blue. This will have been a mother who has treated you poorly (and others) many many times in the past? Don’t expose your baby to her.

Your mother is behaving like a child. I would not give in to the silent treatment manipulation.

This is not on you, it's on her. If she wants to see her grandchild, she can.

You aren't being in any way unreasonable. My dm was regularly driving 6 hours to visit me when I had a baby. It's ridiculous to expect you to do all the traveling.

But the larger issue seems to be your unsupportive partner. They shouldn't be "helping out", they have a responsibility to do half.

Can you try a family hub? Make connections with other mums in similar positions?

I would personally canoe up the Amazon to see my grandchild and indeed my children so find this hard to understand!

Well done for asserting a boundary OP. If your mum has no disabilities and is able to travel then she should be taking turns to come to you. Don't allow her to manipulate you.

What do you mean when you say your partner is 'quite judgemental'? Of you, or your mum?

How often are you going? Can you reduce your visits? e.g. if weekly, just go every 2-3 weeks instead? The time she misses in the middle is when she would come to you, and if she doesn't then it's her loss.

Set your boundaries and let her sit with it. Yes, of course, it’s nice for you to visit her a few times a year. But with small children our families 90% of the time came to us. They have all the free time in the world and are healthy enough to travel. Job done.

My mum, however, did refuse to make some changes to her quite dysfunctional life to enable her to continue to have a relationship with her grandchildren. I was very clear that if she wanted to be in their lives she had to do X. She didn’t want to do X. Made all sorts of excuses. Faked it that she was and lied to me. When I caught her out, she said, fine, I’m never changing, if that means I never see my grandchildren again, then so be it!

And so it was. She hasn’t seen them in 6 years. She was so determined to stick to her guns, so I’ve let her. Frankly, life is a lot more peaceful now and I have no regrets. My children are very happy and well adjusted and having the sort of childhood I wish my parents could have provided.

How old is your Mum? Does she work? Does she have an active life outside the home?

She’s having a temper tantrum to try and train you into giving in. Not giving in will give you excellent practice for when your DS gets older?

Close relatives of ours tried the exact same thing when our children were very small. It lasted for two weeks and then they realised that not speaking to us equals not seeing the children and they turn up like nothing had ever happened.

They didn’t ever try it again.

Would she be able to visit you and stay over? It's a shame to fall out but I agree the journey sounds grim for you to do often.

Some grandparents aren't that into their grandchildren for whatever reason. It's best to accept that sooner rather than later and make a life and support system that does not rely on her. You will be annoyed and resentful because you expect your mother to do what you want but as your parenting journey progresses you will find a mother's place is in the wrong and some day (sooner than you think) your baby will be telling you that you aren't being the kind of parent they want. That's not to say your request is unreasonable, but she might not be able to accomodate it for reasons you, as her child, know nothing about.

Unless there is going to be a major dripfeed that your mum is bed bound or something, YANBU. As a PP said though, depends how you said it. Have you ever actually invited her to yours?