Not on a hire basis. The only way to do it legally in the UK is if an owner is willing to let someone get in the rear seat (where fitted!). That would be the only way to do it.
Alternatively, go to the US of A (Stallion 51 at Kissimmee).
If your friend wants to fly in a two-seat Spit legally in the UK on a paying basis, your only option is Boultbee at Goodwood.