Seems a reasonable request to me. UK Airports are restricted in the information they can supply as regards braking action on contaminated runways. In most cases you will find the reports are based on an assessment by an Ops/Ranger Vehicle. CAA Regs prohibit the use of Friction Measuring devices in Slush, uncompacted wet snow and standing water greater than 3mm depth. Furthermore they cannot be used when the air temp is less that PS02C.
FODCOM30/2005 and AIC61/1999 are useful docs.
Airports should be capable of providing sufficient data regarding the surface state and its suitability for aircraft operations - but if in doubt why not take a look for yourself! All credit to the FR pilot!.