Right, got out the measuring stick and some bits of curtain rod
Using the CRS Drop spindle, HR steering arm in the upper position, there is bugger all (a mm or two) edge of rim to tie-rod clearance.
With a 185/75 R14 tyre fitted to the HK rim, to the best of my reckoning the tyre protudes from the edge of the rim by 17mm.
Fitting up a 24mm "curtain rod" spacer everything appeared to have plenty of clearance.
I'll be heading off to the engineer's shop tomorrow to get some 25mm spacers priced and most likely made up.