I would say that this is a case a momentary lack of concentration on the part of the driver (being a police officer is irrelevant) same rules apply to them as they do to any other driver.
The driver should always check that it is safe for them to complete their maneouver, he should have checked his mirror signalled his intention then when it was clearly safe to do so complete the action. He said to you I didnt see you so there is an admission of negligence at the time. Yes there will be an issue that you did not have type approved fixed incandensent lights fitted, but I would assess this is likely to mitigate the level of the compensation you would achieve from the drivers insurers, bearing in mind that Police Vehicles are not insured in the same manner that ours are (they normally self indemnify).
The fact that you had been drinking is unlikely to be proven, you werent breathalised (i.e you were not driving a mechanically propelled motor vehicle hence no power to request a sample of breath from you).
I would say seek advice CTC etc and on the balance of probability looks like you have a legitemate claim at the least for your bike and I would say loss of earning etc.
Anyway what do I know I am a copper so flame me! 😆
Good luck
MUTDs