Monarch Section 75 Claim or Disputed Transaction?

I've been affected by the Monarch collapse. I had a flight booked with them (that was not ATOL protected) and paid for with my Virgin credit card.

I contacted Virgin stating that I wanted to make a claim under Section 75 Consumer Credit Act.

They've now sent me a Disputed Transaction form to complete. I'm not sure that disputing the transaction is the way to go (in that I assume that Virgin want to try to pass the issue back to Monarch's administrators).

Can I insist that Virgin deal with it directly themselves (under their joint & several liability) without recourse to Monarch's administrators, or is the disputed transaction route the way to go initially?

In relation to the above, my Section 75 claim is, ultimately, for more than the cost of the flight as I believe Virgin (not Monarch) are also liable for any additional costs incurred in obtaining a replacement flight.