Looking at the core of my collection I've realised that there are 2 gaps (in terms of my own tastes, YMMV):
1) A flieger - a gap I intend to fill with an Archimede
2) A modern chronograph (I have a Seagull 1963 reissue which I really like but the styling is vintage)

What are my options in the 36 to 39mm range? I intend for this to be a keeper, so am willing to save up/sell other pieces for it, so the budget is say £500-£800.
No preference movement wise, but would prefer something with a black dial and a date.
Used is fine as long as it won't be an utter pain to track one down.