£2K? that seems very low!?
Money laundering regulations regarding accepting cash payment relate to businesses but I am not aware they apply to private individuals but I may be wrong.
From what I remember if a business wishes to accept cash payment for high value items they must register with HMC&E. They define a high value sale as in excess of €15,000 or the equivalent in any other currency.
If you have no good reason to suspect he is money laundering then as a private individual I am not sure it is technically your problem.
If it were me my greatest concern would be that some of the notes may turn out to be forged. From my experience some bank branches are very laid back about accepting largish cash deposits whilst others take forever checking every note whilst queues back down the street and customers stress levels turn platinum.
Take another method of payment then as others point out you may end up with an iffy bankers draft.