Thanks for the kind words, Richard.
It weighs just over 7kg. I built it from 19mm pine.
Since you're looking at designs, I'll offer some comments.
It's much taller than necessary for a 12" dob. I'm pretty sure that I left it at the highest position that I will use for the photo.
As you've noted, the weather has prevented me from using it yet, so I've just tested it in the garage. The front brace needs some thought when changing viewing targets so that it doesn't bump into the base of the dob. I'm sure I'll develop a system in time.
As I suspected, pine may not be the best material as the support dowel under the seat is leaving small indentations in the main upright. Let's just call it a prototype and see how it goes in actual use.