Flying VS, LHR-ATL-AVL in Y, holding SAS Gold (STE+). If I credit the flight to VS, can I still access LHR Aspire lounge and the relevant Delta lounge (same day and part of an international itinerary) by using the SAS card? OR do I need to still have the SAS FF# on my booking to do this?
Considering having SAS FF# on booking until accessing LHR lounge and then changing it back to VS for the more useful points. But this may cause an issue at ATL on the transit.

No answers forthcoming on the VS forum so hoping someone here might know the best route to take.