I moved into my house a couple of years ago, we have timber decking, thats looking a bit tired with bits of paint/stain flaking off. Have putthe pressure washed on it as an experiment which stripped it back nicely, but I am not sure what treatment it needs now-there are so many-decking oil, stain, treatment etc-whats best? I just want it to get weathered and lovely and not go mouldy. Its the type with grooves in the planks,
thanks in advance

I certainly wouldn't stain it - it's the natural wood of decking which gives it its appeal.

Give it a couple of coats of decking oil but make sure it's really clean as any marks will stay there once oiled...

I'm no expert but I think you should make a distinction between softwood and hardwood.

Hardwood doesn't need treatment, but if you like the look, you can give it a finish.

Softwood will always need some sort of regular protection treatment.

Most decking (I think) is of the hardwood variety, but you should probably find out what kind yours is and then treat it accordingly.

We have the grooved stuff. We clean it with a stiff brush and washing powder, then oil it. If you want it to look natural and weathered, definitely don't stain it! However with natural and weathered comes stuff you don't want, like mould and grime, so you will probably need to repeat the routine each spring.

it is hardwood decking am sure (but not the best quality stuff unfortunately) it has been stained previously so its all peeling and horrible, but seems to strip back well with a pressure washer. I really dont want to stain it, so reckon will just oil it-but does anyone know whatthe difference is between decking oil and decking 'treatment'?

Decking treatment is restorative - decking oil goes on after the treatment.
I wood (sorry ) use Net-Trol to restore the wood and then Textrol to preserve it.