seemed to take a while for it to all settle, had 3-4 goes at 'dropping into place' but then it was working well - untill his brother asked to borow the laptop and jake left
Nah, I mean that will have some impact but it wouldn't just ramp up like this. It should technically have no/negligible impact because the server is only sending the clients the blocks around them, regardless of where those blocks happen to be. Generating that terrain in the first place will use a lot of CPU etc., but in a way exploring the map prevents that happening so much - it'd be happening all the time on a new map.
I'm just thinking the files got corrupted during the move or something. Or maybe they're just really fragmented (although again that shouldn't ramp up this quick either). It's unlikely but if everything else on the PC is running fine then those files become suspect.
Did you try single player on that same PC kos? If that's fine then maybe shut the server off and point single player at the multiplayer world - rule out problems with the files.
Does this seem more like a file thing or a networking thing?
I can get on fine, and it's great! There's unicorns and kittens and giant stompy robots and custard. I'm not sure why there's custard. You should all play!
Actually, not really. I can't get on either. I assume Kos is trying things out.