I'm humming and harring abbout not renewing my av and using the free one with my bt but I can't find anything online (bt site) that actually tells me what it is bar 'mcafee'.
Is is just a BT branded McAfee Internet Security 22.1 ?
It's McAfee and that's all you need to decide to go for something else (that's a paraphrase of what the founder, John McAfee, has said let alone others here). If you're happy with what you've got the best advice is to stick with it.
It is just a rebadged McAfee product although I am not sure which one.
My advice and that of others on the forum would be not to install BTVirus Protect/McAfee. It can cause problems on some computers and is a resource hog. Do a search of the forum to see the problems.
There are far better free antivirus programs available such as Avast Free and AVG Free. If you are a Windows 10 user, the Microsoft antivirus which comes with that is getting good reviews and is free.