Pursuers of the uneatable sandwiches are frequent (5)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

HUNT (as in Oscar Wilde’s description of foxhunters: “the unspeakable in full pursuit of the uneatable”), containing (sandwiching) A (abbreviation for are = unit measure of area, more often expressed in hectares). Frequent, as a verb = haunt = visit [a place] often.