Yes Ian is dead I'm afraid and although you might find the shop still listed online in business directories, it has definitely closed.
The phone number has been reassigned to a domestic residence.
I wasn't able to find much out about the man, except a) he had a reputation as an "experimental" framebuilder and b) he sadly died young.
I was also puzzled by the tubeset of mine as it was "aero" but lugged, which didn't fit the spec of any of the known aero tubes.
Eventually I realised it had an Italian BB and headset (27.0mm fork crown).
Quite by chance I was browsing Hilary Stone's website and found a Simoncini
(scroll down)described as follows:
"This Italian built Simoncini aero road frame is built from Oria ML25 tubing which has been reshaped into aero profiles on the seat and down tubes. I think it dates from the later 1980s."
Apparently when cycling discovered aerodynamics and Shimano released their AX groupsets, a number of builders were inspired to create aero frames to match. Lacking any OTP aero tubesets, they took round tubes and had them squashed.
Couple of links to my threads: