Put a screw driver through the barrel mount bolt holes and, using another flat ended screwdriver, give a sharp push down on the trigger block to unscrew it from the action. Using your towel or cloth, unscrew the block until it`s almost off. NOW TAKE CARE WITH THE NEXT BIT AS THE MAIN SPRING COULD BE UNDER PRELOAD, THUS THE TRIGGER BLOCK WILL BE PUSHED OFF WITH FORCE.( Please note that this is only intended as a help topic and as such i am not liable for any injury sustained during this operation. If you are unsure how to do any work on your rifle take it to a RFD and let them do the required work for you.)
Now for the trigger unit. Using a center punch drift out the retaining pins that hold the unit in place. As you remove the unit be sure to withdraw the safety, making sure that the spring on the end comes out with it.
First remove the stock and the scope. You are left with the action and barrel.Then remove the barrel hinge bolt , removing the barrel and the shims ,then slide out the piston guide bar.
You should find that the trigger block comes away quite easily if it has the original main spring fitted, but if a replacement spring has been put in then take care as this will be much stronger.Withdraw the spring and the piston. Check the piston seal for wear and tear and if you need to replace it.
To rebuild just reverse this procedure and when it comes to putting in the trigger unit, push down the top bar on the unit to engage the trigger as it was to fire. Then when you put the safety catch back in, pulling the trigger as to fire Will hold the safety in place. Replace the longer pin in the front most hole as this makes it easier to position the unit for the rear pin to be inserted.
Remember...if you are unsure do not attempt to disassemble your rifle but take it to a RFD and let them do the work for you. I am experienced in this sort of thing so this is how i do mine, but i have added this post as a help topic for you i you feel confident enough to give it a go.
Remember...SAFTEY FIRST !