Thank you for the replies, I should have responded sooner!
I still haven't heard back from that doula so I'll contact more and see if we can interview them when we are there for a week in August.
RE my Mum, this will turn into a bit of an essay as I want to try and explain but it's hard! I thought I'd said but I haven't, we'll actually be living with my parents as long as they don't drive me mad before the birth so they will be around. Surprisingly my Mum is quite excited about me moving back in, we agreed it before starting TTC and we actually asked if it would be okay with them to bring a baby in, we didn't expect it to happen so quickly though!
I do find her stressful but I've been slowly building contact back up over the past six months or so (I had gone very low contact after my wedding last year), she knows that our relationship is on very thin ice and if she does anything again I'm out. She tried to guilt trip me about my wedding after the fact and basically lied through her teeth about everything and wasn't happy that whilst I'd been wasted, I actually remembered most of the evening so I could tell her that I knew that she was lying. The whole family seem to have a lot more respect for me since my wedding really, they know that I refuse to take the shit they've put me through in the past any more, but it does worry me that I'll be around them in my most vulnerable state and basically be relying on them for social interaction as I don't really have friends in Essex, only two old school friends who I may or may not see.
We will have our own living space and bedroom on the middle floor though so it's only the kitchen that we're 'sharing' and I will be placing very firm boundaries on our living space. It's actually my Dad who would be more likely to try breaking those boundaries as we've discovered recently with my nephew (never leaves him alone, wakes him up, takes him from where the parents think he is sleeping and wanders off with him without telling them, etc) and we will leave the house if they can't respect our space and make that clear before moving in. It does help that we have pet rats who my Dad hates so I think if they are placed strategically in our living room he will avoid the room 
I'm also going to be extremely frank with them when we move in and tell them that I'm not playing petty games, if there is an issue I expect them to talk to me about it and god forbid they start contacting other family members asking if we're offended again, which happened at Christmas because my Mum turned a simple trip of me visiting my older sister into a massive family palaver which sister didn't want and so refused and said we were going back to the original plan (her, me and nephew then our husbands joining later for a film!) Up until last summer my Mum puppeteered mine and my sister's relationships, she hates that we've gone past it and now organise to see one another without her "supervision" as it's led to us all realising how she's manipulated us into the roles she wants us to play so that she can be the poor helpless Mum stuck in the middle of her bitchy warring daughters.
I am hoping that DH and I living with my parents will be a positive experience, but I'm fully prepared for it to go horribly wrong and we'll have the finances to just go. But it's part of the background as to why I just don't trust my Mum when my mental health is in mind, it's only recently that I've come around to the idea of her caring for my child because of things she said to me when I was a child, but she seems to be much better with my nephew from what I've been told.