I'm sure that you can request that PRS attend your premises and take a sample, although they will not give you a date - they WILL announce themselves on the day. I attend a Jazz/standards open mic session in a venue that also hosts private weddings and other functions with live music. This venue does not have any jukebox or such. After several samples being taken by PRS officrs the PRS fee was in fact REDUCED by a substantial ammount due to the balance and frequency (1 or 2 nights weekly) of Copywrite material and public domain stuff. I can't remember the exact ammounts, but it was something like from £300 down to £150 p.a. So it is definitely worth contacting the PRS. However, be wary and talk to/get permission from the landlord first as the PRS charge is likely to be stay high or even increase if there is a jukebox, radio, TV or other piped music source active on the premises. Also please do not confuse PRS charges with music/entertainment licensing costs as these are a completely seperate animal!