In november 2006 Thom worked with Nigel on The Eraser in Nigel's studio at The Hospital in Covent Garden in London. This was later confirmed by Stanley Donwood, who had been around the two then, working on the album art.
Following the completion of recordings for his solo project, he joined the band again for further work on new Radiohead material. Colin had written on october 16th that there would be sessions in december, but no Dead Air Space posts were made then, so it's impossible to say when exactly they took place.
Ed mentioned in the december 20th interview that they worked until a week before Christmas. In the same interview he revealed that by the end of the year the band was working on 25-30 songs, but that looking back on the previous sessions they had to realize that the results so far, even though the sessions went really well, simply hadn't been good enough. He mentioned that the band was still very keen on sparse arrangements, and that 'Nude' was the one song they had recorded properly so far.
Stanley again joined the band in december. Given below are the two futher (and the final) posts from his 'Tachistoscope' blog. As vague and obscure as they are, the first of them actually indicates that these december sessions took place at Radiohead's own studio in Oxfordshire.