Well, there's the update...
I didn't get a call back on Monday morning as promised, so I chased on Monday afternoon. The guy I spoke to told me they didn't get back to me due to all the snow and stuff... Fair enough, I suppose.
He told me he had communicated my issues to the workshop, "as he saw them". (Which basically means, I think, that he told them I complained of a crack that he is adamant wasn't there when it left Toyota.)
He said the workshop were "not interested."
But then he followed up by saying they would repair the damage anyway, as a gesture of good faith. So I can take my car in once the weather has cleared up, and they'll sort it out.
So, all's well that ends well, I guess. It could have gone worse...