"Staff costs I'd guess at 4 FTE"
Perhaps, but helpful staff seem to be few and far between, which means that regulars started going elsewhere a long time ago and their recommendations had a direct effect on other purchases.
Dale Carnegie's maxim on negative experiences holds true even today.
In any case, unlike RS or Farnell, Maplins turned into a cheap gadget shop a long time ago, but unlike the average cheap tat shop they weren't cheap. As such (Like PeaSeeWhirled) they became the supplier of last resort on a Sunday afternoon when you absolutely needed something today.
I'm surprised they lasted this long. It's clear they've been on life support and the _only_ viable way forward would have been downsizing back to being a mailorder business with a counter at the warehouse.