LX200 Meade Bolts

Please can someone confirm the specs of the bolts that fit into the
underside of the base plate of the LX200 10" scope?

Poking aorund on the web, MAPUG and by direct measurement the central
1/2" bolt appears to be US AUC 1/2" 13tpi (as opposed to UK BSW 1/2"
12tpi). The latter might fit at a pinch but could damage the threads in
a soft aluminium casting.

And the three smaller bolts appear to be something like 3/8" 16tpi
(for which there is a roughly equivalent BSW bolt).

I am reluctant to force anything and Whitworth bolts are not all that
common in the UK these days so it would be a special order. As far as I
can tell US AUC bolts are as rare as hens teeth in the UK.

Any suggestions where I might buy the right parts on this side of the pond?

Regards,
Martin Brown