A written off car is harder to sell on again, and if being sold on, it needs to be disclosed. So unless you intend keeping it, it's best to use it as you intend to. Spares and breaking.
Re-insuring it once it is repaired is not a problem I don't think, but I seem to remember that if you repair it yourself, it would need inspecting by an independant garage. I MAY BE WRONG, so someone correct me if I am.
