Some excellent advice there, many thanks for the replies.
Formationfoto
The turn at Harwich was simply to keep me well to the east of the Wattisham stub, but you make a good point about being able to follow the A140 from Ipswich – this would probably make life a lot easier.
Thanks again for taking the trouble to reply - all I need now is some decent weather. Ideas on a postcard please . . .