I believe the oil seal has gone in my turbo whistling when accelerate and excessive oil in turbo.

Mines the 2006 2.0tdci 140hp non dpf when searching for one there's various that apparently fit different models of engine and car eg kuga galaxy etc which would fit mine or is it just one from 2.0 with same hp that will fit cheers ian

The exact part number or firm guidance from supplier using VIN or if second hand (probably last resort) ability to return - but you don't want to do that job twice?
Also concrete diagnosis after inspection for any other possible leaks and definite evidence of play and oil at turbo itself rather than a vague "belief". Oil will contaminate intercooler?

Had the turbo off housing seems fine no play no sign of leaks elsewhere just excessive oil in turbo and the noise when accelerating to go off 

I'm unsure how to confirm that the oil leak is actually coming from the turbo seals.
My only test would be to check for radial (most worrying) and axial play (less worrying but still evidence of wear)?
OR blockage of the drain pipe leading to the seals being overwhelmed?
As turbos run at extreme rotational speeds with very tight tolerances any obvious play needs investigation.
What is the service history, have the oil and filter been changed regularly?
As it is such a major job, after that, I'd go to an expert with a good reputation and previous recommendations for advice.
There's still the matter of possible boost leak which may be confirmed by a professional smoke test if a visual check or looking and listening for boost leaks with car on a ramp and engine running doesn't show anything?

If the turbo is off now, you can block one oil port and then add pressure (or vacuum) to the other port.  That should prove whether the seal is leaking or not.

There's nothing clever about turbo oil, it literally just goes in one side, around the centre bearing, and out the other side.

Leaking oil seals don't create a whining noise.  That can only come from shaft play or damaged fins.  In some cases, turbos do just whine without being faulty.  I bought a Vectra many years ago with a whining turbo, sounded like a police siren, but it worked fine for the entire year I owned it, then went on to be a taxi for many years afterwards.

There will also always be oil inside the turbo and intercooler pipes on modern diesels due to the PCV system.  Oil always gets past the separator and ends up coating the air intake pipework.  Again that isn't a surefire test for turbo oil seal leakage.

I had a smoke test done a while ago before the whine just to check for leaks couldn't find any suppose could of developed one since then. Fitted the turbo back on after removed it as needed to use car sat on my driveway at moment till I get chance to remove again and get it checked properly.