Alea jacta est...
I've looked around - and thought hard... I understand fully the advice that an air-driven gun is much more reliable and damages the wood less and may cost £20 in an uninflated world.
The help and advice on here has been really useful. Even if you don't follow all of the advice, it is great to be able to make a decision that is well informed. I have worked in wood for over 65 years - some of that time professionally - but the plethora of toys now available makes me weep with envy(!)
But two factors sway me. First is the fact that I'm going to need this beast on a job down in a Deepest Welsh Valley - so transporting a compressor as well as everything else will be a right pita. Second is that I only have around 10sqm of workshop space and I really can't justify taking up the space of a compressor, even though the ability to blast air around dusty crevices - and spray paint like Repair Shop Dom - as well as driving brads neatly and jam-free.
So I've ordered a Ryobi cordless beast. I have plenty of Makita batteries - so I've also ordered a Badaptor (thank you, whoever suggested that on here!) Hope I don't regret it!!!
(Sadly, the kit will arrive promptly - and then have to sit around, unused, till the Badaptor wends its slow way towards the Man Cave...)