Going on maternity leave while at risk of redundancy: ask the expert

My company announced in March / April time that they would be reducing numbers and therefore we would have to apply for a role. This was shortly after I had found out I was pregnant. My line manager and task manager were informed as I felt I was struggling and as I was worried about whether this would impact my application. I was told it was bad timing by my task manager and told not to worry by my line manager. I applied for a role in my exiting team at the same level and two others (we were encouraged to apply for 3) in different teams, same level. There then followed a period of waiting where I was signed off with hyperemesis. On my return I was told I was unsuccessful and was therefore at formal risk of redundancy.  The pregnancy was then known by everyone. During the time since then (1st June) I have appealed this decision due to the way the application forms were scored as I felt last year’s rating was used when I was not in the role long due to maternity leave. This was unsuccessful. I was then given three months’ notice, giving me a last working day of the day before my estimated due date. I have obviously been applying for jobs internally, but cannot really go externally as I would lose the right to SMP, although I do understand I could apply for Maternity Allowance. I have had a few interviews, but not been successful. I put in to leave early on maternity leave which was accepted. I have been signed off for several weeks now with hyperemesis. However, I attended an interview last week which again I was unsuccessful for. My line manager is saying that there will be some interviews held next week (which may be when I have started maternity leave) but I will have to travel for these 1.5 hours each way on public transport, which I don’t really fancy but will do if I have to. My question is whilst I am on maternity leave – what do the company have to do to fulfil their legal obligations to me? It is a very large company so there are new roles coming up on the vacancies list pretty much daily, although obviously not all are suitable for me, but I am certain that at least one a week (if not more) would be. What do I have to do whilst on maternity leave? Do I have to attend all interviews offered? Do I have to keep my eye on the vacancies board and apply for jobs etc.?