i've decided to go for it, and have applied for a foundation degree course at my local college. It is classed as full time, altough, I won't be living in or anything (though married with three kids it's certainly tempting!) Anyway, my husband says we might get a big council tax reduction while I study. Does anyone know if this is true? I can't find anything about it on the college or UCAS websites.
You won't.
What your busband is probably referring to is that full-time students are not 'counted' for the purposes of council tax calculations.
Assuming that your husband is the only other adult living in the house, you may be eligible for a 25% reduction in council tax, as a 'single adult person occupancy' house.