Insurance claim advice please ???

[Jamie Summers]

Hi,
A couple of weeks ago I was hit by a taxi driver in London who was trying to overtake me approaching a set of traffic lights. I took the guy's details and reg no. He works for a very reputable London cab firm - Addison Lee. They have a big fleet of fully liveried black Fiat Ulysses.
My insurers (Elephant) claim that the registration number I gave them is "not on the database". Now whilst it's conceivable that I copied the reg no down wrongly, my insurers have the details of the driver and the taxi firm so surely it shouldn't be too difficult for them to hand over the details of their insurers and the correct registration number - or am I kidding myself ??
Elephant think they know who the insurers are and have contacted them but have had no response. I have a horrible feeling this is sliding towards an 'uninsured driver' scenario. Is there anything I can do ? What obligation do the insurers or the taxi firm have to give out details if I did copy the reg no down incorrectly. I appreciate this would effectively mean them incriminating themselves. Is there anything I can do ?

Any advice would be much appreciated.

Thanks,

Jamie