Thanks for all your good wishes, it worked, we have a pass! What a relief!
Thanks to everyone who has contributed with parts, advice and encouragement. Special thanks to Chris, @CL290005, not only for the help, but also the support and trailering my car to the test station.
The examiner at Leighton Buzzard was thorough, but fair, and let us fix a few small issues as we went along. First up we had to add some cable ties to the HT leads as a couple had more than 300mm between fixings. One headlight didn't function properly as some idiot (me) had the wires to the bulb the wrong way round.
A real bit of good fortune followed. In our haste with the headlamp, it wasn't located properly, and fell out when the examiner was driving it. It didn't break and was soon back in.
Next we had to reposition the front indicators to give the correct angle of view from the opposite side of the car, again soon rectified.
All in all a positive experience. Now to get registration sorted and strip it down to paint the GRP bits, fix a noisy front wheel bearing and fit the roll bar.
Need to make a decision on a screen, either fit the full screen, or go Brooklands aero screens, not sure at the moment.
Now to sit in a darkened room for a bit ( and contemplate the list of 'after IVA' jobs Myra has kindly compiled for me).
More info soon, and hopefully be out and about in it while the weather lasts.