
Thanks everyone...I think we've either identified a gap in the market or else there is a very good but completely (to me) obscure reason why we don't have a cheapo solution that fits onto a mixer tap.
When I started trawling round a week or so ago the guy at B&Q showed me their cheapest solution (as per MarianneB)--I was reluctant to take off the faucet I have to replace it with something that doesn't 'go' with the rest of an expensive bathroom makeover. Their faucet and hand shower set that is closest to what we have was over £250, which I suppose is a deal better than the £375 the plumber specialists quoted for the matching single valve and wall mounted hand shower, but is still way more than I want to pay. This is the only bathroom in the house, so I wasn't keen to have a garden hose attachment either, I would like to have something more permanent.
I bought the Argos attachment (which read in the catalogue that you could use it for a single tap), but this still turned out to have two attachments...duly returned....*SIGH*...and so does the Amazon gizmo.
Pookin, if tying a knot in the other rubber tube works I would give it a go--has anyone tried this and/or has the blessed rubber thingy shot off the end of the faucet???
I have a roofed extension at the back of the kitchen but haven't really got space in our tiny back yard to install a dog tub without sacking the tumble dryer. At this rate I might have to think about that--certainly lifting and restraining dogs, bending down over them in the bathroom upstairs, then having all three go nuts racing round the house shaking and rolling everywhere (my bed is a favourite if they can get to it) is not an ideal solution. The next house I have must have a dog wet room :)
In the meantime any ideas gratefully received!