The router codes were admin admin when I re-set the router the first time and I didn't change them. So I re-set again and immediately set an access password for the router which is very strong. That seems to have done the trick, along with a new password for the network.. The original key was a sequence of letters, number, symbols and punctuation so how easy would that have been to crack?
I should add that my friend received an email fro his ISP telling him to choose a new password (for email) as his account had been compromised!
Dell Studio1558 with Win7 Home Premium
HP Pavilion netbook Win8 6GB RAM
IE11 and Live Mail
BT Infinity via HH3
(Virgin 100Mbs as backup)