Little update with some progress. I’m now the proud owner of a ST Hub - great xmas present 
All done switching out backboxes to accommodate the fibaro dimmer module, and almost ready to order them, plus a few TKB TZ69E wall plugs for controlling some appliances and lamps. The guys at Vesternet have been amazing.
Was finding it pretty tough to justify paying nearly £2000 just for switches and sockets, and have fortunately come across Scolmore’s Definity and Minigrid system which will let me kit the house out with all the same switches and sockets (even slightly better, as they do a 3-way retractive switch module which will allow me to dim up and down), for less than half the cost!
Check them out here: https://www.scolmore.com/products/definity/
And best prices online I’ve found here: http://www.peclights.com/shop/wiring-accessories/click-switches--sockets
Will head over to my nearest stockist later today to check out what the quality is like 