I might have to go to UK in November and I'm starting to get a bit stressed and already losing a bit of sleep.

Main problem being 'no bum guns'.

I have wracked my brains for a way around this but just can't think of anything. Help !

You will find plenty of bum guns, they might not be in places that you want to visit, but that's a different story.

Wet wipes for babies are available everywhere, they should do the trick.

Bum guns, unless installed in a specific and convoluted manner, violate UK water bylaws.

The reason for this is because of the potential to contaminate the potable water supply.

The Japanese do a portable bum gun.

Google is your friend.