A squarepusher is a masher, a gigolo. A man who gets all dressed up to go flirt with the ladies, or a military man, or officer of the peace, who puts on his uniform to look important while trying to bag some broads.

It is, in other words, an actual word, and not something made up by Tom Jenkinson. I thought that is was just an IDM neologism until encountering the following passage, Edy Boardman's words, in the Circe episode of Joyce's Ulysses:

I seen you up Faithful place with your squarepusher, the greaser off the railway, in his cometobed hat.

There's an earlier reference in Ulysses too, back in the Lestrygonians episode, in Bloom's interior monologue:

Easily twig a man used to uniform. Squarepushing up against a backdoor.

I'm sure that the title of the Squarepusher 12" Bubble and Squeak has entirely different connotations to those who don't know that it's a breakfast dish. But no one I've spoken to, in the US or in the British Isles, seems to know squarepusher.