Hi Guys
Just found a bit of wiper research I did 10 years ago which may help on this problem, but a little experimentation may still be required. All parts should be available from the suppliers, so shop around.

MGB Wiper wheel boxes
Roadster ‘62 - BHA4324
‘63-67 -520275
‘67 onwards 37H7738

GT ‘65 - 67 AAU1073
‘67 onwards AAU1073
(most of these look like Unipart numbers)

Long (21/2”) MGB wheel box has 32 teeth
Short (2”) BL Mini wheel box has 32 teeth

Also available in 40 teeth = Less travel

Wiper motor cranks available from 90deg. - 130deg.

Standard ali screen NG fitting is 95deg.

SVA screen uses the 100deg. Crank. But felt this could be extended to 105deg.at the time.

I do have some further info, but as this is what I used at the time, it should solve your NG problems for you.

Regards - Dave

Thanks for the comprehensive reply. It seems that I need the SVA one at 100 Degrees. Thanks

Just thought I might resurrect this previous post of mine as I am now at the wiper stage. In the end I bought the windscreen pack from Findhorn as it included all of the extras and by the time I had sourced them it would've cost nearly as much as the pack. The majority of the cost is the windscreen anyway.
I have been studyinhg the wheelboxes and as Dave mentioned above there are different wheel boxes for different MG Models. I spoke with a chap at Moss London (Very Helpful) and he went through the differences. The GT ones have 1.75" spindles whereas the Roadster ones have 2.5" spindles. As my donor was a GT it has the 1.75" ones.
Unfortunatly the bezels and bushes seem not to have a flat angle between them. It appears that the GT scuttle where the wipers come through is profiled. Obviously the NG TF scuttle is flat.

My question is do I need the longer wheel boxes from a Roadster and does the roadster have flat mating surfaces ( albeit at about 45 degrees). I have asked Findhorn and am still awaiting a response.

Thanks in advance.
Pete