Satan 17
"But the thing I was most surprised about is that they said that as long as you have a valid licence and IR you can simulate IFR with screens on a VFR flight without anybody else on board qualified or not!"
Clearly the person you spoke to was a Clerk who knows nothing about the Rules of the Air.
Rule 6
Simulated instrument flight
6. An aircraft shall not be flown in simulated instrument flight conditions unless:
(a) the aircraft is fitted with dual controls which are functioning properly;
(b) an additional pilot (in this rule called a "safety pilot") is carried in a second control seat of the aircraft for the purpose of rendering such assistance as may be necessary to the pilot flying the aircraft; and
(c) if the safety pilot's field of vision is not adequate both forward and to each side of the aircraft, a third person, being a competent observer, occupies a position in the aircraft which from his field of vision makes good the deficiencies in that of the safety pilot, and from which he can readily communicate with the safety pilot.
For the purposes of this rule the expression "simulated instrument flight" means a flight during which mechanical or optical devices are used in order to reduce the field of vision or the range of visibility from the cockpit of the aircraft.
You don't need to write to the CAA with a load of questions about what you can and can't do when all of the answers are available on the web for you to read for yourself.