That would be an ill informed club/club member, sadly it happens. I would encourage you to maybe try another local club if there are any.
PADI Rescue Diver is considered equivalent as a BSAC Sports Diver. If you just wished to dive with a BSAC club you could continue with your existing qualification with the club consulting the SALT (Statement of Alternative Learning Table)
http://www.bsac.com/core/core_picker/download.asp?id=10131
Should you wish to continue training within the BSAC Diver Training Program then you would cross over as above, fill in any gaps you might have and then continue with the BSAC training but you need a cross over pack rather than a "regular" pack (usually cost about £10 more because the have the qualification book etc in them).
My club's intake each year is probably about 50-50 on "new" divers and other agency divers, your experience is pretty much makes me want to bang my head against a wall.....
It's true there are differences in the training (as there are between most agencies) but for the most part these are relatively minor at the lower levels (no insult intended).
When we get to Dive Master and levels above that crossing I encourage crossovers to do the BSAC Dive Leader course as well but what they are "allowed" to dive is still based on their existing qualification.
I encourage them to do it because everyone who has done it in my club has found it useful, it covers in more detail aspects such as trip planning, tides, weather in relation to diving in the UK.
With regards to the OP. The "normal" we see for beginners is Oct on the right, SPG on the left. As soon as multiple cylinders come into play it generally changes all over the place. Its find what works for you and your buddy.