Would like to get the best possible 21mm watch straps for my seamaster 300 - I know there are straps available on the web but few are exclusive Whereas if the lugs 22mm the availability of top notch straps is endless. Does anybody have advice on where to get real quality straps for 21mm lugs please.
Your best bet is to go custom-made, especially if you're looking for "best possible," "real quality." A good number of strap sources will be more than happy to put one together for you, depending on the style you're looking for. In this case, Google should turn up a few good places to start.
Look at http://www.watch-band-center.com/shop2/index.php/user/watchstrap/suche/1/ . Go for watch strap finder . There you can search for 21 mm band . There are over 130 different bands .
Yep look specifically at the 21mm section. Over 100 straps! But having said that, if none of them look suitable, go the custom strap route. I did for my 21mm strap and never regretted it!
Count these folks among the finest: http://www.camillefournet.com/en/ They are the OEM supplier to top watch companies (Patek Philippe and others).