To feel like I’m a bit of a crap parent?

[Bananaandpears]

And I always thought I wouldn’t be. But I have a 12.5 month old who doesn’t sleep, has no routine, doesn’t eat particularly well and somehow I’m just really struggling

She’s still up now and that’s fairly typical. I really struggle to get her to sleep. Then when she’s down she wakes every 90 minutes. I don’t mind her waking up but it does worry me a bit that she doesn’t seem to ever have a decent block of sleep say from 8 pm - 2am.

Just feel like sleep and diet are such basic things and I’m getting them wrong.

Mine woke lots around that age, no long stretches of sleep. It was exhausting. It is normal. Sleep is developmental.
I'm assuming you are in the UK. So, just for a little perspective, in other countries it would be completely normal for your child not to be asleep yet. Babies have another nap around 7 ish and wake after an hour or so, then go to bed around the same time as their parents.
So, be kind to yourself and be realistic about what babies are like, and how little control you have over them.

Dd 1 = put into a routine and slept through the night on her own, in own room from about 6 months. Now 8.5 years old and still sleeps really well at night and in own room.

DD 2 = refused routine, refuses to sleep away from me, now 5.5 years old and only way we all get a half decent sleep is if we keep her bed as an extension of mine and have her next to me and even then she doesn't always sleep through the night without waking up once or twice!

I am ready for bed way before dd

My first never slept. Over a year before he slept through the night. Naps were hugely irregular, mostly 30-40 minutes a day. Friends would talk about their kid's 9:30am nap whereas my DC's nap could be any time between 7:00 and 11am, no two days the same. My best friend's son was the same age and slept through the night from about 6 weeks and had 3 hour naps every day. I became absolutely obsessed with sleep and tried everything.

I think there is a relationship between food and sleep, and he definitely slept better once he got a bit bigger (he was a very small, skinny baby) only thing that helped a bit was giving things like custard, rice pudding, greek yogurt before the last feed of the day as it filled his tummy a bit more than milk and kept him full through the night.

My second DC was a massive chubby chubster and slept through the night by the 3rd or 4th week. There was nothing I did differently. It's nothing you are doing or aren't doing, it's just your baby's own unique rhythms working themselves out.

Hang in there 💐

Oh yes, mine did 5-10 min power naps, about 3 times a day, didn’t have a hot cup of tea for years, I tell you

If you want to implement a routine maybe ask the nursery for a copy of theirs and work from that?

Once you have a solid routine the sleep issues may begin to resolve themselves. Humans including babies like predictably and it helps the brain to sleep if it knows thats the expectation after lunch or after bath etc