Indeed a steal if this is as it seems: a Columbus steel Genius frame/fork with Shimano Ultegra for the rock-bottom price of £140?
I'd be thinking this mobile "mechanic" was more like a mobile thief!
I won't tell...
as the post above says there was a shop in Saltash (Cornwall, for us in other countries) that sold these French-made frames either as bare sets or built up and the finish is customarily the same red as OP's. Years have been mentioned as both '95 and '97...
Even if it turns out to be a lower-grade tubing than Genius (nothing here to say it is, just looking for some gloom) it's still one crazy-good deal for your money!