Were you asking about the equivalent Bentleys, that would be easy, but unfortunatley the useful little volume "20 years of Crewe Bentleys" that contains all the statistics one could ever need on Crewe-built Bentleys, does not include R-R badged cars. If it is of any help, however, approximately 20% of S1-3 production was LHD and maybe a similar proportion applies to cloud 1-3?

I am sure that there must be an equivalent publication givig statistics on the R-R cars - try calling Hunt House.

S.1:
3,072 Standard
35 LWB
431 Continental
of which LHD:
563 Standard
12 LWB
115 Continental

S.2:
1,865 Standard
57 LWB
388 Continental
of which LHD:
398 Standard
27 LWB
152 Continental

S.3:
1,286 Standard
32 LWB
312 Continental
of which LHD:
165 Standard
12 LWB
80 Continental

Delivered to the USA (second largest market after the UK):

S.1:
290 Standard
6 LWB
73 Continental

S.2:
216 Standard
13 LWB
92 Continental

S.3:
77 Standard
7 LWB
51 Continental

presumably all LHD.

Yes, R-R brand much better known than Bentley (they had a factory there in the '20s), which is why the Silver Dawn was built - an R-type for the US market (albeit with less perfomance due to the single carburettor).