This just doesn't make sense to me at all. If the vendors are selling as the persons entitled to become the registered owners then they will have to stamp their deed of transfer, now or before closing, with any consequent interest or penalties if there has been a delay. If this is a genuine subsale, then they are selling on the strenght of a contract and the transfer will be from the original vendor. Either way it is straightforward. If your first solicitor said otherwise, then they are wrong but obviously you already know that and have retained the services of a new solicitor.