After a few attempts at other methods (e-mail links etc) I managed via Playstore to download the VPN on the Chromebook. However the anti-virus package via the same method took ages to load to about 65% then stopped - tried on two occasions - doesn't work.
I understand that Bitdefender doesn't work on some Chromebooks (wish I knew that before I signed up) but if that's the case why have I managed to load the VPN on this one but not the anti-virus ?