7 month old won't sleep in new cot/on new mattress

[bunny2019]

Looking for some advice and to see if any other parents have experienced the same and what they did.
We have a 7 month old little girl who has now outgrown her Snuzpod. For a number of reasons she ended up co-sleeping in the bed with me (mummy) for a month or so. We have recently got her a new cot and brand new double pocket spring mattress (from John Lewis) but she just won't sleep in it. The cot is inour room for now as we tried in her own room and we felt like she didn't like being by herself. I have to b.feed her to sleep (another challenge) and I am very lucky if I can transfer her to the cot without waking, however most of the time she wakes up and cries and cries until she is picked up.
We have tried sleeping with her sheets so they smell like myself and her daddy but when she is put down, what wakes her up a lot of the time is the noise from the mattress. Is does have a waterproof layer on which makes a crinkly noise when she moves, is this normal or common? Is this a new mattress thing? A John Lewis mattress thing?
So two issues really, she won't sleep in a new cot and when she will the new mattress wakes her up. Any advice? TIA

Your problem is that you have been co sleeping and that you breastfeed her to sleep. She must learn to settle herself. Start with the daytime naps which should always be in the cot

Is it a cot or cot bed? Do you have it in your room?

If you're happy to continue co-sleeping, you can take one side off a cot bed, drill holes for the base so the mattress is flush with your mattress, then fix the beds together and continue to co-sleep.

Ime some babies just don't sleep alone until they're a bit older, and that's always been fine with me (once I realised that it was just one of those things and embraced it, I felt much happier actually). They were all sleeping alone by around 15months.