Spade Grip History

Hello all,
please could any one help me to identify a spade grip I have?
It was my late fathers, the spade grip was given to him some years ago by a friends father who worked for a company in the late 1940s early 1950s he used to drive a lorry for the company and at the time his job was taking Spitfires/Hurricanes etc. to the breakers, my father had a set of Spitfire wheels as well, they were used to make a small trailer that was used on the farm for years until the trailer was sold in the farm sale in 1984, went for around a tenner I think.
The spade grip I have has a AH 2040 stamped on the front of it, the construction looks to be aluminium, with a crinkly shrink wrapped black covering around the grip up towards the brass fire button that has safe and fire marked on it.
On the inside bottom of the grip are stamped the following: PATENT DUNLOP APPLIED FOR
On the back of the brass Fire button housing are some small stamps in the brass as follows: B DR E and there is also JR50
30
I have tried to attach some photos of the Spade grip, but they will not upload, I will keep trying!

Kind regards,

Mark