Suzeman
Regarding regulations for snow clearance in UK - CAP168 (CAA Aerodrome Licensing) Chapter 3, Appendix 3D has the detail. Basically clear the runway full length and width to "black top" together with anti-icing to provide friction levels that are safe for aircraft use.
All the airports should do it this way. It's fine once the runway is cleared and some taxiways are available but one of the major problems are the stands many of which just can't be cleared because of parked aircraft. Also the ground handling can be treacherous in such poor conditions. Manchester is not alone in experiencing this type of situation as it's occurred many times at other airports during heavy snowfall and freezing temperatures.