Advice pls re pet flap for dog & cat

[Snowfish]

Advice please. We have a medium crossbreed dog (12kg) and a regular size cat (3-4kg). The dog used to be able to use the cat flap as a pup but he is now too big (can squeeze out but not get back in again!). So we will be replacing our existing cat flap with a new pet flap to be used by both dog & cat. Would like advice please on brands & sizes and also whether we should put the flap in the door or the wall. Thanks in advance xxx

We have a PetSafe Staywell Original 2-Way Pet Door in the back door and have always bought that band. Love them. And as we now have a GSD who squeezes herself through the flap installed when we only had terriers, she has broken parts of it and they replace just the broken parts, if needs be. Great stuff.

PS Our GSD also squeezes out but can't seem to come back in again, lol.

Thanks Lime