Taiga Flycatcher: third for the UK

I was lucky enough to be invited to Shetland with a crew of excellent birders (I was very much in the shadow of their knowledge). We went to check out a Red-breasted Flycatcher found by our guide Brydon Thomason, a few hundred yards from his family's home on Fetlar, last Tuesday. Luckily, the bird was still present in the Sycamore-filled garden of the Tresta Manse owned by a great couple, Peter and Janet.
However, one glimpse at the bird by Martin Garner and Roger Riddington and they were making noises about the bird not being an RbF at all but a Taiga Flycatcher. If so, it would be just the third record for the UK, so they were (we all were) rather keen to get better looks at the wee beastie.
The bird was very active and making broad sweeping itineraries around the greater garden. After quit a while of trying to pin it down, RR came up with a plan to divide the duties. I was assigned to try to get photos within the walled part of the garden with most Sycamore cover. Dominic Mitchell was the photographer for the remainder of the garden, MG and RR with BT chased around for better, clinching views and Fiona Barclay videoed as much as she could.
After several hours of waiting, the bird finally gave up enough views to convince the team as to its ID and present enough photographic opportunities to show the key features.
In a nutshell, note the grey (not buffy, rufous or yellowish) breast; buffy lower flanks; grey lores and face, clean pale eyering, brown cap; all dark bill, lacking pale base; grey neck sides; even, whitish tertials, lacking 'nail' ends; black base of tail extending further up the upper tail coverts, and darker then the 'black' rectrices.
There was considerable excitement to say the least...