unfortunately nabby68, you're in a difficult position and it will require some messy messy work. you have 3 options:
1) ask the guy upstairs if they'll let you get access. it's not an unreasonable request, and would only take a day. then route cables as normal practice and drill through joists.
2) route cables as normal practice and drill through joists, accessing only from below. you will have to pull down large amounts of your ceiling (little holes will make your life difficult and probably won't be sufficient- cables need clipping to joists at regular intervals, and you'll need to also get space for a hammer etc..). it's likely you'll end up pulling down a fair amount, and it may be easier to pull down the whole ceiling. replacing the ceiling - get plasterboard, screw on, then get a plasterer in to do the skimming..
3) follow andrew2022's option as his diagram. you'll need a lot of space once again to get your hammer in, so it's not a simple case of patching up. however drilling wouldn't be necessary. if you do this, you'll have to make sure the cable in the wall is in the 'recommended zones'. ask us if you're not sure what this is...
if you drill into joists, you must be aware of building regs as to where you can drill holes (you can't just drill a hole wherever you please), ask for more info if you're taking this option. don't notch, it weakens the joists much much more than a hole. i always clip cables against joists, however some here may take the view that's unneccessary, and you could just let your ceiling support the cables. if you do this, you then wouldn't need to make big holes in your ceiling for hammer etc..
is this ok??
ps are you aware of part p??
//www.diynot.com/forums/viewtopic.php?t=27936
its up to you whether you bother, but you should know.