"Newshound" wrote in message
...
Am I doing the right thing or is there another technique I could try?

Not worth worrying about blocking the holes, probably. Get yourself an
angle
drill so that you can drill the holes square. There's a Ryobi kit with a
standard and an angle drill, plus a pair of 14.4 volt batteries and a big
1
hour charger for about £110 in Screwfix and elsewhere. Probably the best
tool I have bought in the last 20 years.



I am not too confident of leaving the holes unblocked as I opened up one of
them into a
slot and it is now about 1/3 of the joist heght in depth on one side.

Arthur