Cheers for your input folks.
I've now got the tank mounted, and sufficiently unashamed with the job I did, I thought I'd have a go at posting some photos.
The mounting kit that comes with the tank is laughably low quality, and the intended mount setup is shocking.
I went for a different approach, and time will tell if it was a good idea or not.
Photos should explain, but here's what I did...
1-Used 4 1/2" angle grinder to remove elephant ears from frame
2-Cut, punched and folded 3mm stainless plate to mimic acerbis provided plate, but posn tank 15mm further back to prevent foul of triple clamps on tank
3-Cut replacement indicator brackets from Ali angle to prevent indicators fouling tank
4-Cut about 5mm from each of the noggins that hold the rubber bungs under the tank (as mentioned above, tank is a ver tight fit over these)
5-Machined 2 (handed) ali blocks that fit round frame, where ears used to be, allowing oil tube and elec cable to pass through
6-Templated relationship between 3 tapped holes in each side of the tank, and the 8.5mm holes in my clamps.
7-Cut this template into 4mm Ali sheet
8-Bolt this lot together with a bit if old inner tube to cushion where required, and a few spacers round the clamp
9-Drill a couple of holes in the RH plate, to re-locate the reg/rect.
I think that was about it, if anyone wants more info, I'd be more than happy to help.
I've got a couple of the rear tank brackets if anyone wants, and I can make up more ali clamp blocks if there's a need.