Hi Andy
Either the tilecutter isn't set up to process the 1:10k files or the parameters in the config file need tweaking somehow. Perhaps OS would like to comment?
The one way round it I've found is to scale the tiles to 5000x5000, the same as Streetview, and process those with the tilecutter. The resolution isn't as good, although text is legible, but the rescaling was a quick one using...
2009-07-01 11:23:59 UTC in OSGB Web Map Tools