Agree, I'd be much better if I could manage the hours IO540 suggests.
As he said, an IFR departure (outside CAS) only requires you to book one with ATC. Unfortunately at Oxford they are usually booked up for tests &c. Very irritating when they then don't use the slots they've booked and you sit there waiting for your slot watching nothing taxying out...
Advantage of an IFR departure, though, is that if you have nice ATC they will coordinate with your first en-route frequency, and if they have no radar will arrange to hand you over to a LARS provider or similar PDQ after departure. This is great when you are busy with the climb &c. as all you have to do is follow the departure procedure and do as you are told, and it's calculated to give you terrain clearance and procedural separation until you get onto radar. Several times safer than scud-running to the ATZ boundary and then punching into IMC below MSA - there's a dodgy minute or so when you are IMC below MSA and not on a standard procedure.
Tim