Steve it is your lucky day....
Barnes 1904-1906
George A Barnes of Lewisham, London entered the market using Stevens engines of 2.75, 3 or 3.5hp. He offered both a solo and forecar, the latter having a twin exhaust pipes that ran down to a single silencer.
For 1905 the forecar could have a 5hp water-cooled engine or a 4hp air-cooled engine one, the latter also availalbe for the solo, lighter versions of which used a 2.25 engine.
The extract above was taken from a book by Roy Bacon and Ken Hallworth...and not my words.
I have resized a couple photos of the bikes for you....and hope this helps you with finding out about your Grandfather.