Cases like these are infuriating as it's very difficult to prove. I'd do the following:

-Write down the entire incident whilst it's still fresh in your memory.

-Inform the police and provide a Statement of Complaint. In the statement, make sure you have every detail of the doorman and any witnesses. (Remember the doorman's weight, height, distinguishing marks and features etc.)

-The guy can be identified from his place of work - the police are likely to perform a PNC check on the him which will potentially identify any previous offences. This won't lead to a more likely conviction - and the information may not be disclosed to you - but it could add support to your allegation. My suspicion is that the bouncer has offended before.

• Follow advice from the Police with this, but I'd immediately put in a complaint with the manager of the bar, and if a solution isn't forthcoming, then I'd go higher (the council may be able to provide you with a point of contact for the pub's management company perhaps - I don't have much experience with contacting these people, so I'd do some Googling beforehand)

• Money, as property, is very difficult in proving ownership (as you are aware) -- unless you have serial numbers etc. Had you drawn the cash out from an ATM earlier that evening? Perhaps CCTV covers that area?

I won't answer for the police at the scene, but if it was a busy night they may have had other considerations - they may have concluded, as I have, that enquiries may have been unlikely to catch this guy, and told you that in as many words at the scene. Perhaps they should have been more professional. This bouncer has probably done it before and clearly knows the difficulty in investigating this, especially as you (the patron) was likely drunk, and he's sober. The Court would have a hard time proving this one, and because it's "only" a few quid, I would be chucked out.