In reply to rallymania:
> I'd always thought these style of harnesses were for fast alpine moving together style mountaineering, rather than actual climbing... but now I'm wondering if that thought is correct.
They aren't primarily 'alpine' harnesses any more, the main market for these is as 'group' harnesses sold to Outdoor Centres as they are cheap, basic and fit a very wide range of waist sizes. DMM confuse the issue because 20+ years ago they named their version of this style of harness the 'Alpine'.
> i though the point was that the belay screw gate would be incorrectly orientated which is why they weren't used.
> am i over thinking this?
No you aren't. The harnesses work superbly for abseiling and for numerous other activities but they are useless for belaying. As you spotted, the 'belay loop' is orientated the wrong way and is also too high up.
They are a really poor choice as climbing wall rental harnesses, however I completely understand why climbing walls and outdoor pursuits companies (including ones I work for) use them. The main reason is cost - why buy a larger number of much more expensive 'two size' double buckle harnesses like the absolutely superb Mammut Ophir Rental when they can just buy cheap 'one sizes' group harnesses instead. There is at least one alternative 'one size' harness with a traditional belay loop in the DMM Brenin but unfortunately it is real pain to adjust to such an extent that this can outweigh the advantage of a proper belay loop in group use scenarios.
That said, I do think climbing walls renting out that style of harness (as opposed to just using them for things like kids parties and taster sessions) are setting a really poor example and should ideally invest in some better kit.