So if it is £3.5K per hour and you were able to do as much as 50hrs per year, then you are talking £175K, say £200K total to cover incidentals, per year. Maybe you could skimp it down to £150K.
Even on £10m capital it must feel like quite a lot of money. I mean, you'd have to really want to do it.
If you were worth £50m, on the other hand, you could just do it on a whim.
QDM