i used to have a 1990 model m keyboard (which is what they are based on) and it worked fine up until the day someone spilled 80 proof into it. they are built like tanks.
if you want a more modern option then have a look at deck, das and wasd. they might break your budget though. you could also just look for a specific type of keyswitch ie cherry mx blue (that is what the razers have) and then buy one of the countless other brands not listed by me.
I have a SteelSeries 6GV2, its mechanical, built like a truck so it's super durable... they only thing is it's super basic, no macro keys or extra keys at all. I like it alot, though, I think they have a backlit version as well but it might only be in red not blue. As for the price I think I paid $75 USD, so a hundred pounds should be more than enough.