In the next day or two I shall be buying BA WT+ tickets from LHR to BOS return. Could someone advise me regarding Avios?:

If I buy the tickets with BA direct I will get the Avios but if I buy via lastminute.com (the price is identical) I can get Virgin miles at 2 miles/£. But will this result in less Avios being awarded by BA if I do not purchase direct from BA? These tickets are non-flexible reduced rate tickets so I realise the Avios will be awarded at a reduced rate with BA.

I was hoping to bag Avios, Virgin miles and Amex MR points all in one!

TIA