mmack

Flying SFO-LHR on UA in April. Planning to buy another ticket to fly onward to EDI. Since we will have to change terminals, is it better to try BA or VS? How much time should I allow? There are connecting flights that leave 2+ hrs later, will that be enough time?
We are checking bags. We will fly Business. I recall just going through "transiting passengers" route, not having to pick up my bags.But will BA or VS allow us to check through to EDI? From previous posts it seems not.
Also, looking at the VS sunday 6:40am flight EDI to LHR, arriving 8:10am LHR. Is there eniugh time to transfer to the 10:35am UA flight?

Thanks