2 weeks isn't a great deal of time. I'm sure most on here a paid on a monthly basis anyway. I don't know the ins and outs of contracts, but I can't imagine a promoter would have to pay a fighter just two weeks after.
When my company buys products there's a 30 day window of payment.
The time requirements for paying a Boxer are laid down by the British Boxing Board of Control in the Rules and Regulations. These Rules and Regulations must be observed by all licence holders and a failure to do so could result in the Board bringing disciplinary proceedings against the party in breach.
Regulation 9.37 of the Board's Rules and Regulations require that:
9.37 Promoters shall pay the purse to the Boxer himself or to the Boxer's duly authorised representative if the Boxer so desires. Every Boxer being paid up to £3,000 shall be paid on the evening of the Contest and shall sign for his purse money in a book kept by the Promoter. Such book shall be open to inspection by the Board or Area Council if required. All purse moneys shall be paid within 7 days of the Contest taking place.
I trust that this answers all and any questions regarding payment of purse money to a Boxer.