Thanks for the quick reply Bernard.
Yep, my reg/rec is finally cooked at 123200 miles and it killed the battery in the process (although it may be due to a failed repair/mod I did over a year ago when I replaced the broken moulded in connector with one on a fly lead).
It's good to hear your replacement has lasted so long. I had to make a quick purchase decision to avoid too much lost time off work and bought a new SH650-11. I was a bit concerned though when I found specs for it indicating it's max current is 18A whereas the Tenere's OEM one is 35A. However, it would appear there is a great deal of redundancy built into the OEM one as the Tenere's generator max's out at 20.8A.
So I guess it's just a case of not overdoing the accessories and all will be ok. Maybe even switch to LED indicators? As long as I don't exceed about 250w I guess.

Anyway, I now have a working electrical system........for now!