Well I have often wondered about this, and I found this particularly inspiring. I am glad I do not live or cycle in Harlow any more. What a waste.
Anyway, what I wondered is: what is the legal meaning of the "cyclists dismount" sign is, exactly.
Apart from section 82 which says you should dismount at a level crossing when you see this sign, searching the highway code shows no reference to it. Searching statute law has no references at all. However, as a rectangular blue sign with white lettering it appears to be "informational" in nature in line with the general rules for road signs. I cannot find it on The Traffic Signs Regulations and General Directions 2002 (No. 3113)
So, sort of saying "by the way, in case you needed to know you may find that cyclists dismount at this point". It is not an order or a warning sign. It is in no way instructing cyclists to dismount or do anything.
Maybe if I am following another cyclists that comes to such a sign I should allow for the fact they may stop and dismount. This is something I need to allow for at any time anyway, so hardly a warning and not that useful a sign to tell me that.
So why the hell are we all paying councils to erect signs that basically seem to have no use or meaning?