@martinwiseman2000
I would also say it has nothing to do with the CAN bus.
How many miles has the current tank done?
If it above a certain mileage then maybe it is time to consider replacing it as a serviceable part?
In the end I also had to bite the bullet and change the tank at 86000 miles. At least I did the work so it only cost the price of the tank.
Take a look at the eBay item number as I posted above 285666735004 Now priced at £550 with coupon. Not sure if this is your tank but the supplier is well known and reliable.