Dear Mary: how can I unmask anonymous marathon sponsors?

Q. My son-in-law is running the Paris marathon to raise money for cystic fibrosis research and has sent out a mail shot to friends and family asking to be sponsored via justgiving.com.

He has had a fabulous response. Some people have posted supportive messages alongside their names but have chosen to conceal the amount of money they are donating. Yet two supporters, who have been spectacularly generous, have anonymised their names –although not the giant sums of money that they have pledged. My son-in-law would like to know who these people are – what do you suggest he do?

– A.E., Pewsey

A. For practical reasons certain people make a deliberate choice to remain anonymous when giving money. Think it through. Although the recipient will be unable to thank them and they will get no brownie points, these are by no means pyrrhic payments. Virtue is its own reward, as is anonymity.

Q. I am of the opinion that it is naff to make visitors take off their shoes indoors.