This is the pick of the 3 objects I imaged last night.
The mount was positively singing by this time.

My initial concern about the guide scope being able to handle such a long FL were totally unfounded.
And the Canon 550D was in it's element working at such a low temperature.

This image comprises 12 x 8min @ ISO800
No flats and the only darks I had on hand were to suit 5min subs but I used them anyway. lol
Tonight I'm going to try to crack the 10min barrier!!