Sorry I had completely forgotten about this thread, until your reply.
I finally found time to built up a prototype about 6 or so months ago, over a wet weekend here and took it to work and demonstrated it to my boss and the service technicians.
The first question I was asked was "Ohh, where did you buy that from?"
By this stage, it didn't look anything like I had originally planned it to, with small improvements and a couple of extra features added in.
I've since made 4 other of these units, so now everyone has one, apart from me.
I will grab one at work on Monday and get some pictures, I should have done this when I was building them but the thought never occurred to me.
That boost converter worked phenomenally well, considering it cost so little, which shows how far we've come,
I remember a time when anything "special" like this device would have cost you an arm and a leg.
I bought ten of them when I made the other 4 units and I had one on my bench here, I loaded it up as much as I could and thought it would overheat without a heatsink on the chip, but no, the voltage never faltered either.
So it was good news all round.