My P reg Sporty Is due for the dreaded MOT.Bless her went straight through the last 2 with nothing needed doing and no notifications.This time she needs a bit of welding on chassis.On front no trouble just an elongated bolt hole plate over jobs a" good un" However at the rear the hole is on inside of chassis next to the fuel tank.Not being immortal I need to remove the tank.The query is do I have to/how do I release pressure in fuel system? Geoff H.