I suspect that this doesn't answer the question. The question is what is the minimum requirement to be BS 8599-2 compliant (what is necessary and sufficient to be compliant). Understanding this would allow the judgement of whether it is possible to have a compliant kit that is useable on a bicycle.
It might be, for example, a requirement that there be a 20lb weight in the kit (not a big deal in a car) but prohibitive on a bicycle.
It would appear that the actual regulations are behind a paywall.
http://shop.bsigroup.com/ProductDetail/?pid=000000000030284623