Hi,
Ian Rice did one in one of his books, I seem to recall that he moved the front splasher forward to a more accurate setting, removed the coal from the bunker and made up a new cab front with the correct spectacles etc, he also opened out under the boiler and fitted a scale chassis.
I got a scale chassis for the R/R1 off of Ebay some years ago, it was originally made by Andrew Mullins of Branchlines in Exeter, perhaps the new owners still have them in their list?
I know Andrew also did some lost wax castings for the boiler backhead and replacement scale splashers for the front but again not sure if they are still available.
After living in Australia for many years I have found that if something is advertised or reviewed that is pertinent to my modelling needs then I buy it, I would rather be looking at it than for it.
It also means that when I decide something will never get built or is about to be replaced by something RTR, then I maake a judement call as to whether I still need it, and if not off it goes to the auction.
Cheers