Not sure if it is a real Lemham or rebodied. Here is some info on them when I was helping the seller research these cars.
Julian Booty or Peter Rix at Lenham contact info
https://www.lenhamsportscars.com/postman.php and see if they have any records
of 505 CYF
Here's a pic of the later body style (rear quarter window)
https://www.gerardsgarage.com/GarageContent/UniqueSprites/lenham/Lenham.htm
The Lenham Coupe body came in 2 derivatives - an early one, and a late one.
The 'early' one didn't have rear side quarter windows - the later ones did.
Personally - the earlier ones were much better looking than the later ones.
It looked like an E-type from the front - and a bit like a Datsun Z car
(Kamm tail) from the rear. You could just put the Fibreglass Lenham Coupe
body on your Sprite in the 1960's.
The Lenham Motor company also produced a 100 based body that made a 100 look
more like a Silverstone, than a 100, as well as MGB Coupe bodies etc.