When you say clutch solid it it that the pedal wont move down? Could be pedal pivot seized,or master cylinder seal breaking up and a bit blocking the fluid outlet,or like mine last year the flexi pipe collapsed inside blocking it.
Open the bleed valve, if the pedal won't go down the master cylinder is siezed, if the pedal goes down the master cylinder is OK, pop the slave out, see if it's siezed. If the slave is operating OK then it's in the bellhousing and it's probably a gearbox off job. Good luck!