In reply to humptydumpty:
The crag station (not based at Awesome walls stockport) were selling this type of screw by Austrialpin
http://www.alpinsport-basis.de/AustriAlpin-Siko-FX-Eisschraube_1
Don't know if they are still doing them and a goggle search doesn't show good UK distribution.
They work fine and are fairly similar to the Grivel Helix. Mixing the 2 doesn't make for great racking - but that's generally the case mixing brands and models. I think they make a reasonable alterative if you need to get a rack kick started.
I agree that it's certainly possible to find low grade climbs that will take screws e.g. Idwal Stream at grade II/III, it can be more a case of whether you think you need them - but it gets to be a long fall if you cock it up and I recall areas where alternative pro would be hard to come by.