Farquhar says that that effort is not directly related to the Open XML announcement: "Some people think we are adopting Microsoft formats as our standard for digital preservation. This is not right; we are striving to make sure that content we receive in MS formats will be preserved." He continued: "What format will we deliver? We deliver a lot of articles and in many formats. We deliver content in PDF, Office Open, ODF, TIFF —whatever format the customer wants."

Until I read that, your article had given me the disturbing impression that the British Library was standardising on OOXML - essentially making MS Office their standard. In light of the quote I've used, I'm hopeful that they're just going to use it as a 'standard' they import from, much as OpenOffice imports from a variety of formats.
I just hope that things haven't changed in the time sime then…