Was the builder Ian Headon? That would make it the IRH7.
Ford crossflow engine, Renault gearbox, Standard-Triumph front suspension. 5th overall at the 1969 Players No6 final.
Reg for the road! LUO246F.
Wow, well done, as this is indeed one of the numerous IRH specials (though IRH V, not VII) built by my old friend Ian Headon, who sadly passed away early last year. Ian was a lovely chap that gathered quite a collection of cars (Jaguar being his real passion) as well as his own home-built specials that he used for competition.
I will PM you as I am very intrigued how and where you found your information, as I am sure his widow will be fascinated to see any information about him and his cars on-line.
Well done again; two points to you