2 way microchip cat flap for bifold door

[Itsrainingten]

We have a cat flap in our bifold doors. It's a microchip one and we turned it backwards so that we can control who goes out because we have 1 older cat who comes and goes as she pleases and a younger cat who is less sensible and we worry about on the road. So he only gets to go out when we let him out. Both can come in though. The problem is that a massive intruder cat has started to come in. It then gets trapped and freaks out and it's like having a tiger in the house. It's actually quite scary and it smashes stuff. I have seen 2 way controlled cat flaps which is what we need but the "tunnel" part seems quite long so I'm not sure it would work in a bifold (too wide to fold the doors back) can anyone recommend one please?

We have the Petsafe one, fitted into a glass panel.

Ours is petsafe too but it's only lockable in one direction. Can you program both ways on yours?

How is the intruder getting in if it's chip operated? Are they following yours straight through the flap?

It's on backwards to stop the kitten going out unaccompanied. Older cat can go out, youngster can't, both cats can get in. But sadly this means ANY cat can get in and only 1 can get out again. Which was fine until we started to get another coming in. That's why we need one that's programmable in both directions

I don't know what make ours is but we can lock DCat in or lock her out.
No "tunnel". It's in the glass part of the back door.

I've genuinely never heard of any microchip cat flap that lets any random cat in before!

So it wouldn't let in any cat other than ours EXCEPT we have it on backwards. Normally they'll let any cat out but only the cats with the registered microchips in. At the moment we only want it to let out our adult cat, so we switched it so that it needs to read her microchip to open from inside. No other cat can get through in that direction. But it only has the controls on one side (because people are normally just worried about other cats coming in) and so since we've swapped it ANY cat can enter (which is good for the kitten so he can get in when we've let him out but we always know when he's out because he can't get out on his own) but it does mean other cats can get in too. But not out again 😬
Which is why I want one that can be controlled for going in AND out.
Phew. That was long 😂