Bald Brick: It's sorted!!
I changed /etc/adjtime as you advised, still an hour adrift. Then I tried: rightclick on the time/date > Digital clock settings > Time Zones > London was already selected, and I changed the Clock defaults to box to "Europe/London", from "LOCAL". I'm a bit confused, but I think perhaps if I'd changed the digital clock settings to London first off, I might have saved you all this bother
Thanks anyway, I've learned about changing file settings in /etc/, and got more under the hood of PLCOS and KDE, so it's been worth it for me!
Now I have to get the tiling working!