Thanks for the helpful replies.
I decided to follow your good advice and skip the rotator to begin with.
Managed to get everything mounted and aligned this evening - having taken delivery of the lens from amazon around 16.00 - and big surprise, the clouds rolled in even though the forecast was for a clear night. Snapped m42 and m45 through the high clouds anyway as an act of (futile) defiance.
Can anyone recommend a Batinov mask, please? Either to buy or to print. Various designs are advertised but not sure which ones work well.
Cheers, Des