Help with Lister H3 pump strip / rebuild

I've got myself quite nice a nice (no frost damage etc.) H3 pump, after much effort and heating up the valve cover caps (to s*ddin' hot !) I've got the valve caps off and I want to completely strip the pump. Connecting rods are off and so is the air Vessel. Two issues, how do I get the pump plunger (piston) out ? I have drifted the crosshead out and slackened off the gland collars and these are free to slide up and down the piston, the piston moves only so far backwards and forwards - which end of the pump boday should it be removed from, gear end or front ? Do I need to scrape out all the old packing before I can get the piston out (I don't see why really) Can you get to the rear (gear end) of the piston ? I assume it comes out the front but I cannot get it out. Second question, how do I remove the valve cages (I assume these screw into the cast iron) and how do I access the lower set of valves (front and rear) ? Any help from those that may have undertaken any of this would be much appreciated.
Regs
Dale

I've moved on with this, its actually fairly straightforward, the rear of the pump has a separate casting (I didn't know that to start with) which is the gear carrier and rear end cover of the main pump body. On my pump (once I managed to prise off the gear carrier and cover) I extracted the piston from the back, all I have to do now is free off the valve cages (or whatever they are called), valve retainers perhaps? And replace the thick rubber washers. Its a clever design as it doesn't rely on a seal on the piston itself. I'll try harder before asking a dumb question on here again, think first, post question later - much later, we live and occasionally learn eh!

Slim - you are not alone Squire - the beauty of the forum is we can ask all the daft questions we want - but they are only daft if you know the answer - otherwise they are the most complicated questions we think are possible - crack on Sir - no such thing as a daft question

Although I have found a bit of gentle banter seems to find those of us who are newbies....

The H3 is a nice piece of kit - when you can and if you are feleing like sharing your progress a few pictures of before and after would go down well.

Best

Hamish