PC Advisor is owned by IDG,and PC Pro is owned by Dennis Publishing.
The 3x£2.00 offer may well be correct, as these sort of offers are always being made by various magazine companies.I get the 'flyers' for these offers on a regular basis. It makes you wonder sometimes, if it is wise to stay loyal and subscribe to a particular magazine, with all the special offers and free gifts floating about.
Did the person who contacted you, mention their company address etc. If it was a place in Market Harborough-Leicestershire, then this company acts for many magazines, and they are quite legit.A word of warning though,watch who you give your c/c or d/d details to, especially on a cold call basis..