Porsche 911 value?

I'm looking to sell my 1982 Porsche 911 3.0 SC and want to know a realistic
value.
It has 135000 miles , is Quartz metallic in colour with a black/brown
leather interior.I have a black leather with red piping interior awaiting
fitment.
Condition is OK , with a few rust bubbles but nothing major.There is a huge
history file and it will have 12 months MOT. Reg No is 911 *XL.
Its only for sale as I'm not using it , preferring to use a bike (motor not
pushbike) to get to work....

Cheers

Steve