Got Avast Mobile Security on my tab, and its started throwing up security warnings whilst im browsing MG. Anyone else getting this or know anything?

Not at the moment, and BitDefender is usually quite high even on false positives, not to mention actual issues. Flagged the site before at some point when a malware-infected ad was running, remember there was a news post after it was banned, but haven't seen anything now so far.

I have Avast Antivirus on my desktop. No warning received.

After leaving here, it threw a warning about every website I went on. Eventually gave up for the night, and nothing today,so no idea what went on...

Faulty definitions update?

Honestly, I really wouldn't know where to look for an explanation.

Avast hasn't showed any more warnings, and it updated about 4 hours ago, so if it is a problem with Avast, that seems to have sorted it.