In message , Clive Backham
writes
I know this has been discussed many times before, and I've done a
Google Groups search looking for an answer, but I'm hoping that some
very specific questions might elicit some useful extra info.

First, some background (sorry for the length). We have a Staywell 31
cat flap. This is the kind with the passive RFID type device on the
collar.

That seems very high tech. We use the basic Staywell magnetically
operated model, which seems to work fine. However it cannot be set to
only allow only one cat in. Fortunately there are no other cats around
here that use the same system.

Magic and Ebony have a habit of losing their collars quite regularly and
replacements are quite expensive for what they are.
--
Martin Jay