Sorry, but I see little artistic merit in 'tweaking' the works of Van Gogh, Hockney, et al. For contemporary artwork, I'd much rather view the photography of someone like Martin Parr or the architectural triumphs of Norman Foster.
David Mach does little more than any (weak) A-level Art student could achieve.
I missed his show in Edinburgh so can't really comment much. I hope to catch up with some of his work eventually as he intrigues me. Possibly he is as Chris describes.