All you can do right now is engage in all the support being offered to you. It might actually help you to get better. Ok, so things didn't go well last time with Vilidium but things are different now and maybe something will click into place.

Your employer is right, there has to be a point where either you are able to return to work or they have to let you go but there are a few more steps to try before that happens so don't be bullied by them. Also if you do reach a stalemate DO NOT resign. They will tell you that you have to cos you aren't living up to contractual duties but thats not true. In fact to terminate your contract grounds of incapacity they have to pay you any accued holiday and 1 weeks pay for each full year you have been in their employment (you may need to check that with your union rep or CAB) but if you resign you get nothing.