A lot of brickies don't count openings as it saves time. They have to form openings which include lintels etc so its easier just measuring across them - works out roughly the same price.
£12 for blockwork is about right, £22-24 for brickwork is about average these days too.
£150/170 for a bricklayer for a day is about right.
This is pretty much right. We pay our brickies 'through the openings' which includes steel/stone lintels and cills and all window reveals etc.
Otherwise there are different rates for forming reveals, installing cills/lintels/expansion joints/DPC's etc that need to be added into the m2 of the brickwork quantity alone.
Rates per 1000 will vary around the country. Here in Scotland most LO subbies are paying between £250 - £280 which is £15 - £17 per m2, but this will vary on the type of brick (or stone) used, bond style, pointing style etc.
To find the m2/1000 (or vice versa) you divide or multiply by 16.6
Rates also vary depending on quantity of work, brickies will accept lower m2 rates if there are lots of houses to build (as in our case) not so much for a one off private build
You don't say if it's traditional build or timber kit, nor how much brick vs block there is but as for timescales, a clad timber kit would take a couple of weeks, traditional about 4 weeks, assuming you're on top of all the scaffold requirements/materials etc.
Lot's of variables, best to get a few reputable local guys round and get the quotes. Small completion date bonuses are a good idea.
Oh, and never pay brickies on a day rate for a job like this, it's not in your best interest.