Back to work and baby doesn't get on with mother in law!

So I'm going back to work now my baby is 8 months old. My mother in law lives 2 doors away and was planning on having her 2 days a week. She's happy to and did so with the other grandchildren. She hadn't seen her during lockdown (we didn't see anyone) but has been getting used to her since. She's absolutely fine with her when I'm around and goes to her for cuddles, milk and comfort. However we've been leaving her with mil for a few hours to get used to each other before full days and she cries hysterically as soon as I leave until I get back. Despite mil trying to sing/play/feed/comfort nothing works until I walk back in. Please help I have no idea what I'm going to do next week when I go back to work!