Sending money regularly from uk to usa

1) Some options in the "Online services" section here:
https://www.moneysavingexpert.com/banking/foreign-currency-exchange/

For sending to the USA, and especially in small amounts, look for a firm that can pay the US recipient by ACH (which is roughly the US equivalent of Faster Payments) and not by SWIFT or "International Wire", which can incur charges that would make up a substantial percentage on a $500 transfer.

Transferwise can certainly do this; not sure about the others on that list.

2) Forgive me addressing a point you didn't ask, but given the experiences people tend to have with timeshares and the like, are you sure this "holiday bond" is a legit deal?