Looking around, pending the imminent replacement of our bathroom (the
one where I gave up boxing in pipework in July last year)

Screwfix do a shower mixer that looks like an unfeasibly high flow
rate compared to most other bar mixers, their ref: 31693 - apparently
does 8L/min at 0.1bar - does this sound "right" to those who've fitted
them ?

While i'm at it, how the hell do you figure out what your pressure is?

We're on a combi-boiler (WB28SIii), have good cold water pressure, and
at the moment, c/o the kitchen sink, it chucks out 9 litres of hot
water per minute - although I believe from a previous thread you can't
equate throughput with pressure.

I've tried to play safe when ordering taps for the bath / sink by
going for 0.2bar jobbies, but I don't know how low I should be setting
my sights at for a shower mixer valve (i.e. would a 0.5bar be ok ?)

Any advice would be much appreciated :-}

While i'm at it, because of the difference in pressures, would you fit
a pressure equalising valve / pressure reducing valve on the cold ?

Last but not least, and this might sound really dumb :-} but as a
shower fed by a combi won't get any hot water for several seconds, how
does the temperature setting work - does it let the hot flow until it
gets to temp, then let cold through ?