How about a system where JPA justs puts £x in my pay chit for everyday away from home and thats it. Seems to work for a vast number of private organisations around the world and removes the need to spend £100k per station to save £15.60 per year on someone who had 2 glasses of wine with dinner rather than 1!
It used to be a bit like that in the 1980s for MOD(PE). Depending on your grade, you were given a set amount for accommodation. Some youth hostels and cheaper B&Bs were kept very busy.