2.7 tdi turbo

Well hi folks, I'm back. Woe, woe and thrice woe. Could be a long post here so put kettle on. As previously reported, my beloved (?) Allroad has been suffering from a severe reduction of boost.  After much perusal here, head scratching and two scans, the second being done with an Audi compatible unit, the consensus of opinion is that the variable geometry vanes in the turbo housing are stuck solid and presumably in the maximum boost position as the engine starts immediately and idles smoothly without any kind of misfire or camchain rattle whatsoever.......but just a GENTLE tap of the throttle and the waste gate immediately dumps boost. Literally just revving to 15-1600 rpm and you can quite clearly hear the waste gate in operation. The electronic gizmo that operates the vanes works smoothly when disconnected but the lever(?) it attaches to does not move at all. As previously mentioned,  I  tend to drive in a moderate fashion and rarely boot the throttle ie rather like a chauffeur with a VIP in the back. Belatedly I realise now that I should have driven rather more aggressively more often but here we are..... If anyone wants to look up the mot history and age, this can be done by perusing yankeepapafiftysixromeodeltayankee (here's hoping that'll confuse the bots). So...do I attempt to refurbish or replace the turbo at what cost? or do I offer up the vehicle to someone here (preferably) who can do this and if so, what could I expect in terms of remuneration. The car is quite capable of driving itself on to a trailer. The work I have done or had done is a battery and alternator 3 years ago, rear suspension air bags replaced, crankshaft vibration damper replaced 2 years ago and front ride height sensors this year. It has had a yearly or 10k miles oil service religiously. My local garage ( trusted!) has quoted me about £1500 ish to supply and fit a new turbo with 12 month guarantee. So what should I do? Answers very much appreciated.