You can use any oil or acrilyc paint.
I would recommend dulux satinwood(once)firstly it is self undercoating so the coverage is good and unlike gloss satin doesn't tend to lose its colour. Gloss will start to lose its whiteness after a while and turn yellow
This would depend on the customer and the budget you would want to spend. Due to Farrow and Ball would cost more than say Deluxe Paint or Lora Ashley. then if you want mat'' silk'' or egg shell'' gloss'' Or oil based paint or Water Based. So many brands that do differ with the finish. The answer I would give is work with your Decorator and make good use of his or her Knowledge and use some samples to see what you like best.
Depending on the finish.bare wood i would wax laqueur and use a resin based varnish. Painted surfaces then an oilbased undercoat and gloss
DependING on your choice if you have clean wood you could staine it then varnish it. If it's painting over paint got to be oak you got diffent shades. Hope this helped.
if its a listed building you must use the same paint/type and colours its already in. if you want the flat look i would suggest farrow and ballbut most paint manufacturers have a wide choice of paints for such projects.
Any gloss (gloss, satin, silk finish) will do. Best always to buy the highest quality you afford. Some customers also prefer low odour and/or eco friendly paint. some prefer the paint to be sprayed rather than brushed to give a better finish. The rest is down to the state of the wood and I could only establish that by visiting to give an estimate. For instance, older houses may have many layers of paint on the wood - does the customer require just a paint over or a strip down?
apply two coats of paint to undercoat first and the second is a satinwood suggest deluxe. Regards PNZ