Yes they are. It was a cycle paramedic first on the scene when I last had to call for an ambulance. He was with me within 2 minutes, the van turning up after about 5. Sadly, too late already, but somehow the bike connection was a tiny, tiny comfort and distraction.
They are often to be seen patrolling the centre of York. I saw one once, looking embarrassed, because the rain had got into his two-tone and shorted it, and it was making all sorts of odd whines and funny noises...
There is, or was (I haven't seen any recently,) a couple in Leeds. Apparently very fast at getting to incidents in heavy traffic, though that isn't really surprising.
The bikes were equipped with a fairly loud ambulance-sounding siren and a totally ineffective flashing blue LED lamp. I once observed a paramedic trying to ride through a junction against a red light whilst on 'blues and twos.' It appeared that drivers could hear the siren and were being a little cautious, but as they could not see an emergency vehicle were proceeding anyway (as would be their right, as they had the green light) and treating the hi-viz cyclist as any other RLJer.