Hi Stefan.
Firstly, greetings from the usually sunny Isle of Anglesey, I hope you're able to get what you're looking for.
On that subject, have you tried Maplin? They used to have stuff like what you are after, dunno if they still do.
www.maplin.co.uk Failing that, maybe look up an Army & Navy store. I know there is one in Bangor North Wales, on the High Street or a bigger one at Denbigh:
http://www.denbigharmysurplus.co.uk/
Try those.