Hi Shygirlie, so sorry to hear about your awful situation. Please don't give up hope - you are not trapped, it just feels that way because you are still living with someone who seems intent on making you miserable. Talking from experience, it will seem much less hopeless when you get a place of your own and are able to put some space between you and your mum.
I second Attilla's suggestion of speaking to Womans Aid, but would also perhaps try to speak to your local citizen's advice too.
Update for everyone else: spoke to my brother tonight and it all went ok really. We had a lot of other stuff to talk about, the I mentioned the conversation at the wedding and how he was obviously still upset about things between me and my parents. I said i was sorry that it was affecting him and that he still felt awkward. He said that he did find it awkward, which i sympathised with. Db mentioned that parents seemed to have had a good time at the wedding and that they enjoyed spending some time chatting to us at the wedding, which i confirmed was perfectly nice, chatting, making small talk etc. DB said that these things just take time sometimes and i comfirmed that this sometimes be the case, but i did not want to go back to the way things used to be. He said that even if we met briefly when i came to visit, for a couple of hours, it would only be a few hours a year, so not that bad. I said that i did not intend to meet up etc in the foreseesble future, and didn't want to chat on the phone etc, as I have been unhappy with things for many years. I did say i was perfectly happy to send cards, make small talk at the odd family event etc. He seemed ok with this but said it's dad he feels sorry for, i empathised and said that we have differing opinions re dad. So it was a bit vague and wishy-washy but at least we addressed things and their seemed to be some empathy on both sides, which is positive, even if DB seems to be hopeful of things improving in time. I said that i can understand that this is all very awkward but i didn't want it to create tension between us, which he seemed to agree with. So i think actually things are ok really.
Also, our first nephew was delivered lat night by emegency c section. He is premature, so will be in incubator for next couple weeks, but mum and baby doing well. Looking forward to meeting him and having lots of cuddles. Went to Tescos aftere work to buy some baby bits and a conratulations card, when excitement faded and was suddenly fighting back the tears. Don't have kids, and not planned for future. Complicated but morstly due to DH not wanting them, which I accept, and me spending most of my life being too scared to have kids incase i turned out like mum, and ended up making their lives a misery. Most of the time i am fine with things, but i suddenly felt very sad for what i will never have. So i bought myself a big bunch of flowers and some chocolate to help the moment pass. We're hoping to see him tomorrow, but not sure due to hospital visiting rules being a bit awkward