We had an amazing one in our old house-heavy and rubbery and say on the oven floor not budging.
I bought one from Amazon recently which was like plasticky paper and just floats around all over the place (fan oven) and tries to escape when you open the door!
Typically I can't remember where my other one came from so was wondering if anyone could point me in the direction of something that sounds similar?
Amazon is very confusing as well. Some of them say 'oven floor liners' but then the description says it not suitable for putting on the oven floor?!