I use this one when I put my MacBooks on a laptop stand:
AZIO MK MAC Wired Mechanical Backlit keyboard.
Not sure if it has an UK layout, you might have to research the Q&A on the page, or read product description, or contact their support.
It is basically one of the very few choices for: (1) backlit, (2) mechanical, (3) wired keyboard with a Mac layout.
I like it. The keys are little harder to press compared to my PC keyboard but I found it enjoyable and much better than Apple’s official keyboards, be it the builtin on the MacBooks or the external Bluetooth ones. Only drawback for you might be the white backlighting of the keys which, combined with white keys, makes it slightly annoying to use in daylight if you want to look for a key. Still though, it’s a very slight annoyance, I promise you. Unless you use it 99% of the time under bright sunlight, it won’t ever be a problem. Plus you can switch off the lighting during the day – many people do that but not me; I keep the backlight all the time.
How can you even ask that?! Only a non-mechanical keyboard user can ask that.
Seriously though, mechanical keyboards improve your typing, like a lot. You have much more robust key pressing feedback. Before them I was constantly second-guessing if a keystroke has been registered and this severely hampered my workflow. Afterwards, these keyboards are now pretty much a subconscious extension of my will.