Solved - MJW #387 - Birsay Triumph 250cc 1956

[woodinsight]

What is the name of this small racing car and what engine powered it?

[woodinsight]

I wonder if an expert knows what this rather small racing machine is?

[woodinsight]

Also promoting this one to the PAFW section

[woodinsight]

Moving it to the Pros for hopefully some action

[faksta]

Spanish and Bultaco engined?

[woodinsight]

Not Spanish but powered by a well-known motorcycle engine

[woodinsight]

Time for a clue. It is British, name is six letters but don't forget I need the engine make also for a point.

[shamrock]

The Birsay , 250cc Triumph engine , built and driven of Leeds England , 1956

[woodinsight]

The Birsay , 250cc Triumph engine , built and driven of Leeds England , 1956

Congratulations!
That's exactly what this small single seater is.

[Paul Jaray]

Can anyone explain which one is a Birsay?
The puzzle car or one of these:
1st pic came from Motor Sport Magazine
2nd pic from Bonhams
They are all Triumph-powered built by McArdell (according to MSM) or McCardell (according to Bonhams).

[nicanary]

I found this image of an early Birsay. The narrative suggested that aboiut 12 cars were built, of which 4 survive. The yellow car sold by Bonhams was thought to be one of the later-built cars.