Well. I ended up losing both those auctions and ive been watching so many auctions come and go and done so many searches for cranksets in the past week that its giving me really bad anxiety thinking i'll never be able to pick up a replacement on the cheap. So rather than deepening my anxiety ive just gone ahead and ordered a Tiagra 4700 off amazon.
There probably will be a small weight penalty but i cant deal with this dark cloud hanging over my head anymore. its for an all-weather bike anyway. Putting a 105 or Ultegra on it would have been nice if the price was right but this bike is going to get thrashed so its not really the end of the world.
I originally didnt want to pay over £60 for the 6750 ultegra part so i lost that auction. Then i increased my budget for the 105 but got outbid by someone who apparently wanted it more than i did because I had it at £120 then he sniped me for £140 at the last few seconds and i was still working up through the bids because i didnt want to go a quid over and before i knew it, the auction had ended.
Im sure it will shift just as well if not better than the Pro Wheel Ounce 721 that its replacing.
Though Im surprised that nobody here had some spare parts lying around that i could buy
(and if we're talking about looks - It looks like the same crankset on my cube anyway which is a 6800 Ultegra)