I bought the equivalent set to this (two heads and stands, 60x60cm softbox, small umbrella and rolling case etc) in 2008,
second hand, for £600. Mine are the (slightly) newer GM500 units.
My set was in virtually as new condition and the price I paid was very reasonable at the time. I'd say that £380 for this set now is a little overpriced.
If you could knock the price down (£300, maybe?) and test them to ensure that they're in full working order they still wouldn't be too bad a buy, though.
My GM500s are still working faultlessly. As previously mentioned, they really are built to last under pretty heavy use.
A few years after buying them I also bought a
second hand Esprit 1500 (can be set to 500, 1000 or 1500WS in addition to the infinitely variable five stops of adjustment). That's still going strong too.
I do take the points made above about more modern units of notionally lower power being as powerful, more consistent etc. But I am still perfectly happy with my lights and have no intention of replacing them for the foreseeable future.
I don't use them much at home, though I do occasionally do so for portraits or whatever and they're great for that, no problem. For smaller stuff at home, however, I have a barrelful of Vivitar hotshoe flashes which see plenty of use.
I often use the Bowens for groups of anything up to thirty or so, and for this I don't find them too powerful at all, often running them at full power. I also often use them in 30x120cm stripboxes, gridded and gelled, and in this situation again find them only just powerful enough. This is with a crop-sensor D300s, at my preferred 200 ISO.