An ave £3k per watch, so:
1) JLC Memovox - either with a classy black dial, or a funkier style 70's case.
2) Omega Speedmaster 125.
3) IWC Ingenieur 3521.
4) GP gyromatic hf (preferably no date) in SG.
5) Enicar Sherpa GMT / Traveler.
Other than swimming / diving I can't think of a location or pastime that 1 of these wouldn't suit.
Nice 'problem' to have ;-). Thanks for the post.
Best,
Giles