I have a rear washer and wiper. I used an after market pump mounted at the rear and a small clear plastic bottle that the hose goes into the screw cap, the nozzle is mounted 5 1/2 inches up from the bottom of the removable top on the passenger side next to the door. If you look inside you will see a galvanized reinforcing bracket, the nozzle is just above the top of it, works great. I guess you could use the jug the washer fluid comes in and just change the cap over each time.
1971 series 2a 88, series 3 trans, Fairey OD, owned since 1978.