The Tank™'s diet continues, with another saddle change. I picked up a secondhand Selle Italia Kevlar Gel Flow saddle on Ebay for the princely sum of £40.41. It's quite an old one but is in fair condition and, crucially for my purposes, tips the scales at just 180g. That's pretty light for any saddle, but especially for an MTB-specific one.
Whatever, that's a further 160g shaved off the bike as a whole, bringing the whole thing down to 13.05kg. Not bad considered it started at 14.5...
There is still more to do, but am starting to get to the point where big differences will be hard to make. Still, every little helps, right?