Thank you gentlemen.
I tried capturing my footage again in non-anomorphic, once in 4:3 and once in 16:9. On both occasions, I later (after capturing) went into Sequence Settings and checked the anamorphic 16:9 box.
Having exported both attempts to MPEG4 at 768×576 SD, there doesn’t seem to be any difference in size, quality etc between the two, and to my untrained eye they both appear to have the slightly squeezed anamorphic look.
So I think you have cracked it for me. I will capture in DV PAL 48 khz at 16:9 then change the sequence settings to anamorphic after capturing.
Just to double check, does that sound right to you?
I really do appreciate your help. Many thanks.