Thanks for the kind words, guys!
It did stay good an moist... could maybe have got slightly more tender - I only got it up to about 195F, and I've read 205F is ideal. It stalled for so long at about 160F, I ended doing an unplanned Texas crutch - fortunately it already had that thick bark on it by then, so wasn't a problem.
Pretty sure I'll end up getting a WSM at some point... may have to wait a while though, until the wife has understood why I needed to spend £200 on this BBQ!