The Top Time 2000 was produced from about 1964 and your serial number dates your watch to 1965. Its movement will be a Venus 188 cam lever chronograph or Valjoux 7730 (which is basically a rebranded Venus 188). Value is probably of the order of £1500+ I would guess. Servicing ought to be straightforward enough, excepting possible difficulties with proprietary Breitling bits such as the shock settings on the balance. If you want to know a bit more about these watches, then I wrote three posts documenting my own experience restoring a Top Time 2002 from 1965 (all three of which linked here).
Martin