Thanks all very much for your suggestions.
I used a cloth soaked in white spirit to rub out the residue. Some patches needed quite a bit of rubbing and scrubbing, but got it all out eventually.
Cheers.
I am a DIY newbee and found this forum only last week. Very helpful folks here on this forum !
Last weekend, I had to paint by bathroom ceiling. To prevent the paint getting on the adjacent tiles, I used duct tape that I already had to hand (instead of buying some masking tape - don't laugh...