Hi all, I've not been posting a lot lately due to the arrival of a cat in my house. I know you all have a lot of experience between you and are happy to share it, so hoping for some advice.

My son lost his girlfriend and his flat, so I am looking after the cat for a while, no idea how long. She is 2 years old and never been outside and was very happy. However summer is here, and we can't keep the back door closed all the time. She has been out a few times under supervision, and seems really happy chasing flies, bees around, pouncing on things in the grass. BUT she is attracted to the fence on one side of the garden, and has been over it twice. We had to call her back, and she came eventually. We found the new neighbours had a 'Catwatch' which is supposed to deter cats by giving off an ultrasonic noise. So she got past it, and didn't want to come back. I'm now really nervous of letting her out. She has to learn about the outside world, but I don't want anything to happen to her.
I just wondered if anyone had any advice on how to teach her NOT to go over this fence. I have to be out there with her all the time, watching, and I daren't let her out on her own.
I would love to hear any advice, stories, etc, as I've no experience of this. My previous cats learnt when they were kittens and were easier to control.

thanks for your help

Anne