As for the Tipsy, have not given it much tought however, my first idea would be that a type rating is not required for the tipsy and so an SEP rating would have to be obtained in the normal way using and aircraft with dual controls.
A colleague of mind is the only Tipsy Nipper rated pilot in the world. The CAA gave the owner of the aircraft a one off permission to conduct the 1179 test from the side of the runway at Ipswich as an 'observed test'. dont forget you need a specific type rating in your licence to do public transport or aerial work, well you used to anyway.
law doesn't require designation of a commander pre-flight.
It does by implication, otherwise the pre flight action of a commander cannot be carried out, plus the commander has to 'book out'
You are mis-understanding 'law'
The law dosnt state it is illegal to drive across a dual carriagway at 100 mph, roll over 6 time and burst into flame but it does state that it is an offence to drive without due care and attention or dangerously on the public highway.