Well, after using the Shooting Shed bore guides for a little while now, I thought it might be useful to update this thread.
There is a problem by design with them and not one that I can see a ready answer to except for me not to use them! It is this: Even when dry patching the bore, you simply can never tell when you have a clean bore because the patches always come out blackened (at least when using jags and patches) where they have taken some of the oxidised aluminium off the inside of the bore guides. The Aluminium also seems to react with cleaning chemicals which erode the aluminium. I think I'll have to chalk this one up to experience and simply try and find a supplier of PTFE or other inert bore guides. Lesson learnt! They are beautifully made though and may be ok if not using such close fitting jags or different chemicals perhaps. It doesn't detract though from the superb customer service offered by David and Christel at The Shooting Shed.