Veg/Meat Preperation Rooms Cooling Load

Hello all, new to the forum and entering with (i hope) a fairly basic query. Been a long time since I've done any refrigeration calcs in earnest (was also during uni days so doesn't really count in the real world! :P) and looking for a bit of guidance.

Job is basically to produce two rooms held at 12 deg C (plus or minus a few degrees is no great problem). These are meat and veg preperation rooms located within a working commercial kitchen. I'm struggling to remember all the things I need to consider, and expecially how to factor in replacement fresh air. Also making I think far too many assumptions!!

What I have so far....

Each room is identical in size (2.8m x 3.5m x 2.4m), each with two external walls (u-value 0.45), two internal walls (u-value 0.2) which are adjacent to a working kitchen (assumed to be 35 deg C, 75% RH). Ceiling will aso be u-value 0.2. Entry to space is through 'cold stop' curtains (u-value 0.67)

Internal gains come from equip (roughly 1kW), 1 person and 4 36 w lights.

Cooling load for air/vent requirement is stumping though, especially with how to factor in the 'cold stop' curtain door.

Any guidance is hugely appreciated, and please be gentle - its been a while since all these words were part of my vocabulary!

NB Location is on Scotland also, so no hugely hot days to contend with!!