Hi Sami - in the correspondence from the war office in 1936, he was referred to has Chateworthy (although this was an error of the office, not Robert). His father had been called Clapworthy at one point as well, once again by someone else!! And the application in 1936 was refused as he had deserted. I haven't as yet found him using any other first name, just Robert.
I came across a document that had been transcribed as Clatsworthy, but in the original it was quite obviously Clateworthy - don't know if that is the same one you have seen - but it wouldn't surprise me if it was yet another one, as there seem to be so many variations!!
Lilybell, thanks for those documents - that's fantastic. I have a subscription for that site, but it doesn't cover Canada!
GG