Hi everyone - thanks for the responses to my OP.
We feel the answer will be a call blocker as we have been registered with the TPS for a long time. The problem is that TPS doesn't stop nuisance calls from abroad and, as Newquay says, the beggars find a way around it!
We have ordered a call blocker for about £20 - every time we answer a call we can push a button to save the number as one we are happy to receive calls from, or press the other button which will block any further calls from that number.
Will be a pain for a while but hopefully will deter them?
Had a call this morning at 7.40am! Just the time when, if the phone rings you think it's a problem with our elderly neighbour or a problem with the grandchildren, so it's got to be answered.
Caller display is great except I don't have my specs on at that time of day 
Gooseberry crop has disappeared
AIBU To Be So Annoyed at the Stupidity of This
Father's Day Sunday — nobody makes cards for this type of dad



