[pygorex]

There's a few things you can do:

* Drop the move to London requirement and allow him to telecommute. This could especially be appealing as he's working below rate. * Hire him on at a full salary with the understanding that he will defer a significant portion of his salary. He can defer it towards equity (maybe with a multiplier and definitely with a cliff) or defer until you close another round of funding (at which point he is paid a bonus equal to his deferred salary). * Depending on how well you know and trust this person: give him a small equity stake up front with a regular vesting schedule every 6 months.