The problem was drilling the floor tiles. I tried several methods...
1) Bit of making tape over "proposed hole". Tap "X" with sharp screw to chip surface. Drill gently with masonsy drill on slow speed. Result: Chewed up masking tape and no hole.
2) Drill more vigorously with masonsy drill on slow speed. Result: No hole but wearing through tile surface slowly.
3) Drill with increasing vigour on highest speed. Result: No hole but wearing through tile surface less slowly.
4) Get out SDS drill and touch tile. Result: Shattered tile.
Fix tiles down and plan to drill in place. 2 days later...
5) Go to Focus and but "proper" tile drill for £4.95 Result: Que for 15 minues only to be told they won't accept a credit card for under £5. Faff about trying to find some cash in pockets as wallet at home (only brought out to pay account at BM) Found cash, bought drill, vowed never to return.
6) Mark up new tile. Start drilling hole, slow then high speed with proper tile drill. Result: Tile drill "lightly marks" surface and glows red as which point I stopped.
Repeat steps 2 and 3 for around 30 minutes.
7) Grab angle grinder and try and think of how to drill a hole with a 9" diamond blade? Result: Tea
8) Drill on slow speed with "proper" tiles drill using cold tea as a lubricant. Result: Drill bill snatches and shatters but does drill into the tile by about 3mm.
9) Spend another 30 mins drilling remainder of hole with a newer masonry bit on slow speed. Result: Approximate hole.
10) Repeat above (minus tile drill) for another 4 holes!!!! Result: Go home, drink alcohol and post to NG.