Hi, can anyone help me? I have two female cats (neutered/spayed, not sure which!) and they use a cat flap. The trouble is, so does every male cat in the neighbourhood and of course, they spray.
Is there anything I can buy that will deter the male cats from spraying in my house? I find it so repellent!
Thank you in advance to anyone that answers.

You can get cat flaps that only let your cats through - assuming your cats are chipped that is.
Quite pricey though - £80ish though you can also use them to set a night time curfew which is handy if you get home after its already dark or you want the cat to go out once its light in summer.

I know you can get the microchip ones, but can you give me a link to one that does that and will only let them in (and not our again) after a certain time, because I'd love to have one that did that.

I got the microchip one for mine, and looked around quite a lot - never saw any with a timer on. But you can set them manually to prevent them going out or prevent them coming in, whichever you want.

I have a similar problem though, OP - the local tom sprays all up the door and over the cat flap which both they and me are most unimpressed by

Yeah, I do that with mine, it just requires me (or someone) to be here to do that, would be great if I could put it on a timer so if I did get delayed at work i'd know they were in safe after a certain time

This is the one I've got Pet Porte
It doesn't have a timer, it works on the light level - which saves you having to adjust for daylight every few weeks!
Its not very easy to program though, or maybe I was being a bit thick. Also the installation instructions were a bit still I got there in the end.
It certainly works well - Brooke isn't that keen to go out at night anyway, but we have foxes here so I wanted to be sure as I dont get home 'til after dark in winter.
Shop around as you can get it cheaper from re-sellers.

it makes perfect sense ... definitely a gap in the market there