Fido,
While you're in a spending mood why not replace those rubbish tyres before the weather gets realy bad.
Like Ozwald says the Pirelli P3000 tyres seem quite good. They are a little noisey (at least they are on Cargo suspension) but grip well and give good mileage.
As an experiment I'm trying some Vredestein tyres on Mrs_G's Cargo. They grip well, are quieter than the P3000s and look nice with a directional tread. (See seperate "Tyres" thread).
Post a few pictures of the Doblo when fixed, we'll see if we can spot the join.