£3.5k won't necessarily give you a stupendous punt any more than £200 would, or wouldn't.
I suppose if you're including a nice hotel suite, especially in London, that would cover £3000 then I'd get a favourite out for a couple of hours for the remainder.
Point being, it's not the money, it's the previous experience with the chosen WG that goes some way (but never guarantees) to a "stupendous" punt.
In the OP's hypothetical, I can only imagine the comms involved in arranging such a scenario to be prohibitively off-putting no matter how much cash was involved.