Tappets

Hi my golf gti has been parked up for a year the engine was fine then,I've just ran it up briefly and its tapping quite loud .is it common for the golf to tap due to oil draining from tappets over this period,thanks

Yep. Should sort itself out once the pressure builds up.

Yea all the oil will have slowly drained out over the year

Hope you are putting in some new oil and filter?
New fuel filter and petrol will also help.

You can remove the rotor arm and just turn the engine over a few times with out it starting to increase oil pressure before starting the car to help.