Thanks all, progress is being made! I think given the nature of the work required i.e. working from room to room for a mixture of woodworking and decorative purposes I need to view it from a job-site perspective. I think the other reason to not go down the air powered route in my situation, is where I am from a tool procurement basis, i.e. if I didn't already have expensive battery powered nails guns etc etc it would make going down the air route a lot more practical.
With regards to extractor, Numatic is a new brand to me but I've some browsing they do indeed look like excellent kit and you seem to get more capacity per price point than Festool although with the latter they seem to edge it on warranty/filter but I suspect net net there is little in it and comes down to personal preference or integration with other tools etc.
On the sander vibration stats that was a great shout. I didn't even think to see if they were published. My current cheap Erbaeur is 1.6kg in weight with vibration of 12.7 m/s..... can see why I find it such a pain when I compare to Festool around 1.2kg in weight and vibration down to 3.5 m/s or the Mirka at 1kg and 3.4 m/s. On that note, it does seem that the good quality sanders all fight in a very similar weight when it comes to those stats (although even lower for the air powered kit).
I think from what you have said and from some research that indeed it is worth forking out for the ETS EC if going down that route. I was struggling to find availability for the ETS EC 125, the 150 seems a lot easier to get and then went to the Festool UK website and the 125 is no longer listed in the ETS EC flavour, just ETS so I don't know if they have pulled this product but either way, look at the weight/vibration figures I shouldn't fear the 150. An alternative I found was the MIRKA DEROS 5650CV SOLUTION KIT, coming in at a similar price point but unlike the Festool ETS EC 150, this actively permits interchangeability between 125 and 150 pads (although don't know why you would need to change), however it is 0.2kg lighter than the Festool. I think it's a toss up between the Festool ETS EC 150 & Festool MIDI extractor vs Mirka Deros 5650CV and Numatic NV750 extractor. Nothing really in it when it comes to price and I suspect at the end of the day both would be fine choices. I note the Festool 150 comes in 3 and 5mm strokes, I am guessing for finishing I should opt for the 3mm flavour.
Re battery vs corded, thank you for that info, it makes sense now for me to go down the corded route, the auto start & BT remote seem a great feature on the festool. Do you clip your sander cords to your extraction hose or is that unnecessary?
Finally, for getting into corners on cabinets/doors/wardrobes and so forth, what would encourage you to opt for the Festool 400 RTS vs DTS, i.e. palm vs mouse if you can only pick one?
Thanks again, hopefully can press the buy button in the next 24 hrs as my wife is going away for 2 weeks and won't notice the delivery