My home needs a cat - cat flap logistics

[NeverRTFT]

We have a semi with garden. Had the back of house and kitchen remodelled a couple of years ago so it's frickin impenetrable (having been burgled few years ago). Now I want to instal a cat flap and it's a head scratcher. The options:

Cut a hole in bottom of newly hand made solid wood French doors, possibly not doable due to shaker panel detailing;

Replace a small window pane (think they are called muntins - the kind of windows with a grid of small panes). The windows don't open;

Make a hole in external structural wall;

Fashion something out of the downstairs loo window which is an inexpensive big pane double glazing with small opening at top.

I'm stumped.
Want a cat.
Not really planning to have housebound cat, seems unnecessary when we live in resi area and have garden etc.

Tunnel in wall here too (through two bricks and a load of insulation).

My parents also had a cat tunnel through their wall, it was easily blocked up once their cats were no longer around.

@NeverRTFT Sorry cannot share picture as moved from that house 20 years ago but it was a double glazed upvc window that we put a flap in, well the glaziers made a new window installing the flap and then replaced the old window in the frame. We kept the old window to pop back in when we moved.

Because it was a window rather than door so about 2 foot off the ground DH got a plank of wood and put little bits of wood across the width of the plank so cats could easily walk up it to the windowsill and use flap. Once inside we had a table at just the right height for them. My cats are truly spoilt little darlings

I don't have a cat flap anymore because I now live on a very busy road so I have Katzecure fencing to keep my babies safe and only let them out when I'm home.

Re whether a cat flap is needed - I think every cat and situation is individual. Our cats are young and active and definitely need a cat flap as they're in and out all day long. Boycat in particular will yowl and go crazy if he is locked in for more than 5 mins - he normally spends all day outside but pops in frequently for short food and head massage breaks .

We are also in a high density suburb with a lot of cats, so a window wouldn't cut it. Our cats have been bullied by various neighbourhood cats, and on a few occasions they've burst in the catflap for safety with another cat hot on their heels, knowing the microchip flap would keep their enemy outside.

Our next door neighbours don't have a catflap and their two ragdolls are locked outside while they're are work. The ragdolls are constantly trying to break into our house to get at the cat food (which really traumatises our cats!). If we left a window open, they would be inside like a shot!

On the other hand, my mum lives in a quiet suburb with few other cats around and her elderly cat barely ever goes outside. So I can see why a cat flap would be a necessity in some situations but not others.

Our old cat never had a flap. We did a shed door flap so she had somewhere to hide if she'd done a runner and we'd had to go to work, but she obstinately refused to use it. We'd spend hours playing the in-out game/where's the door into summer.

Before we got the current cats we had a Sureflap microchip flap put in a (new) uPVC door by the supplier, positioned diagonally to the handle so nobody could easily put their hand in the flap and open the door unless they had arms like a gorilla. The cats learned pretty quickly how to use it.

They also found the shed flap quite quickly and we often find one asleep on the shelves. their slaves may have put a cushion there

We are hopefully about to acquire a cat. All our local rescues insist on a cat flat as a pre-requisite for adoption, unless the cat has medical requirements that make them indoor only (which we would prefer not to take on), so we can't really wait and see. We're in a similar situation with no perfect solution, and we're going for a wall tunnel next to the bifolds.

I'm not thrilled about it, but it's the best option for us.