This is indeed the method I'd usually use but to be honest only for a temporary time, ie for an event.Terminate and gland the SWA into a small box and take a flexible lead from there to the 13 Amp plug. If necessary fix the box to the wall to avoid the weight of the SWA from hanging on the plug
We do have stock cables for site temporaries with swa terminated with Ceeform plugs but even then not the smaller sizes of plug/socket. 32A minimum and carefully selecting make.