I've been sent a new contract to sign. I'm on mat leave, can they ask me to sign it or do they need to wait until I'm back? We've all been sent them as part of a change to t&cs but it's complicated and there are various mistakes and issues which I'd need to do lots of emailing or calling about to get resolved and I really just feel at a disadvantage trying to do it from home without contact with colleagues etc. plus I just don't have much time or energy because of looking after the baby. Advice?