As far as Rolls-Royce go, this seems a very confused subject.
From what I understand the RB series were originated in Bristol, although their is no RD series for Derby. The 211 was just a sequential model number, most of which never saw the light of day. The -524 followed from the -22, I think the 5 indicated it was 50,000 lb thrust class, although the -535 was only (originally) 35000lb class. The other letters referred to throttle-push or growth variants of the same engine.
As to why the RB211 didn't get named after a major river (as in Spey, Dart, Tyne, Trent etc.), I've never heard an explanation.