I cannot find any law that states everyone has to be breathalysed where a RTA is involved. It may be normal proceedure but not obligitory (no other option).
In this case the police went against the advice of a paramedic. Motorcyclists in my experience get a raw deal most of the time from ploddy (er.. yer OK officer I know it's for my own safety cough,cough, shocking throat today).
Looking for a prosecution rather than carrying out his first and foremost duty to protect life , limb and property.
Out the corner of his eye someone drags a set off panniers into the distance as he shoves the tube into the bikers mouth "blow as hard as you can mate I know your in pain but do yer best cause if you fail it's an offence". A parmedics request goes unheeded and the results of the breathalyser confirm that the police officer may now have to attend the request over his radio to attend a burglary taking place nearby.