By coincidence, I've just had an email from Which? and it includes a report on anti-virus software. AVG is number 3 in their table, behind Bitdefender and Avast One (both also free).

Their review of AVG concludes:

Expert verdict: Solid protection and even some improvement on last year, such as with USB scanning. However, to rival the best, the 'warning' notifications need to be toned down to improve user experience and not cause unnecessary worry.

2011 Morgan 4/4
1932 Austin 7 Chummy