I lined up to buy some of the ones you sold off - some great deals there...
However, I think the problem is that "in the dictionary" does not automatically equal "of value" - some of the ones you have left are frankly of no commercial use and therefore I suspect won't sell at any price, let alone at 100 pounds.
Remember, the buyer is also facing paying a 35.25 pounds transfer fee so they are effectively paying $200 for very marginal names. If you see what $200 will buy you in .com on the domain forums, it's much less surprising that many of the ones left are not selling.
In general, the transfer fee sets a "floor" to .co.uk sales prices that doesn't exist in .com (since people have to pay 35.25 pounds regardless of the asking price, whereas in .com people can sell for $1 if they want to...) Even without considering the .co.uk/.com value differential, that means that the "quality threshold" at the lower end is MUCH higher in .co.uk than in .com.