I'm looking at one that has been listed as 'Chalwyn' because of the cap to the oil reservoir, but the burner says 'Martin Patent'.
I've just won the auction for the lamp and it's going to cost just over twenty five quid with the shipping, so I might have got myself a bargain.!
The lamp has just arrived and it's a weighty beast.! Coming in at 5lb 13oz and is most certainly Victorian being made out of solid brass. I'll have to measure the hole for the filler cap and see if I can get one of the right diameter.