I think that Tim is thinking othe correct lines with his ALLIN-transfered frame...and the probable link to Holdsworth
My reckoning is that it came from the larger and extended Holdsworth workshop and that it is most likely an F H Grubb frame - Holdsworth bought out the rights to this brand in the 50s early 60s.
In any case It is identical to a Freddie Grubb in my collection..Nervex Serie Legere lugs and bracket (not at all filed down), Clement simple plate drop-outs without the Benelux gear hanger, ans an unsophisticated fork crown from what I can make out.
Grubbs of this type although generally made of Reynolds 531 DB or sometimes 531 Plain gauge..always felt a little on the heavy side. They were unpretentious Club bikes that usually rode well and had few faults.
Allins did have their own brand frames made in their own workshops..or so I was told on a visit to their shop way back in 1952./53. Generally these were very elegant, well-filed and finished - a highly respected brand.
Hope that helps a little
Norris Lockley
Settle UK