Guys - Hope you can offer some advice, what next!
Recently changed my valve stem seals as was smoking when coasting, managed to do it with the head on, took out the old ones and put on the new, reset valve gaps.
Now it constantly seems to blow smoke even when warm and idling, seems more obvious on low revs, driving down the road and there's a big cloud of blue smoke, only when throttle applied. Seems less obvious at 40+ but that could be just the fact i'm going too fast to see it. Could i have not seated the valves seals correctly?
I did notice a diesel leak on my leak off pipe which was quite bad, have just repaired that, don't think it's connected to the blue smoke. Otherwise it seems to run fine, plenty of power, doesn't get bogged down or anything. Have taken intercooler pipes off, doesn't seem to be excessive oil there, had a play with the turbo, some movement, at most 1mm either side.
Am possibly thinking piston rings? Next step is probably to do a compression test?
Am in Leeds, if there happens to be any 200tdi experts close to me who may be able to give me a hand, my first defender so not too clued up on them.

Forgot to add, when replacing the leak off pipe, it was replaced with a clear pipe and i noticed some large air bubbles, do i need to bleed the fuel system? Or does it self bleed, if so could someone give me some advise? many thanks

it self bleeds ,might be worth getting your injectors tested

Check pump timing, might be retarded this gives white smoke but well worth a look, simple to do as well.

If the pump timing is out, could it create the blue oily smelling smoke as well?

I wouldnt be 100 percent of that as diesel smoke has many hue's and different cause's so not as cut and dried as petrol engine's.
But like I said above it's free and easy to check out so got to be worth a look.

Imo blue smoke is always oil, White is water (steam) and black is over fueling.

I've not done oil seals on a landy but I have on motorbikes. I managed to crack a valve guide once and changing valve stem seals made it worse.
I'd do a cylinder pressure test and if that reveals nothing and their is no oil in the inlet manifold from anything up stream (turbo or breathers).
I'd either do the seals again or whip the head off and get the guides done too.

i had this type of smoke too changed stem seals still the same ticking over was smokey when blipping revs it was extra smokey constant revs smokey so i pulled injectors put them in mr muscle oven cleaner cleaned with soft wire brush got all the crap off them and then put them into acetone for an hour or so put em back in little bit of smoke then it cleared and guys what very minimal smoke now will give them a nice steep in injector cleaner or acetone another day such a quick and easy job and its 100 times better now as the injectors were covered in carbon.

Does it smell of burned oil or diesel. You could try an injector cleaner, it sounds like it may be injector related.
Pull the injectors and connect back onto pipe and see if they drip etc using starter motor.

Agreed, could be oil or diesel. Do the compression test, monitor oil consuption, if its oil you should see the change, air in fuel usually gives white smoke. You could run some intector cleaner through it too. In my experence if you can see oil smoke on power and overrun the oil consuption will be under 120 miles/pint which shows up quite fast on the dip stick.