Hi Alistair,
That's a great watch. I have a 105.003-64 which is very similar. I find I wear mine more than the later Speedies that I have. It is lighter & more flimsier, but I prefer it somehow. I have mine on a 7912 bracelet.
I can't see much wrong with yours at all.
All I can see on yours that is wrong is the Bezel is a later replacement. For your watch the dot at the "70" marker should be at the bottom right corner of the zero, the "275" should be almost touching the dot below "300" & the first "E" in "Tachymetre" should have an accent above it, like this => È.
The centre second hand should be the spear shaped hand. You can get these new, but to be honest a new on that watch wouldn't look right.
& of course the pusher.
The rest looks fine.
Have you had the back off yet ? do you know which model/year it is ?
There are a number of bracelets that could have been fitted to the watch.
You should be looking for one of the following 1035, 1501, 1506, 7912.
7912's are now VERY expensive, 1035's are a bit cheaper & you rarely see 1501 or 1506's ( they are even cheaper though )
If you find a bracelet. Make sure it has endpieces. ( marked either 6 or 16 ) these again are VERY rare I have seen a single endpiece for sale for $100.
I bought a Seamaster Deville with a 7912 on it for $450 & sold the watch on. ( & that was a couple of years ago ). I think you will be lucky to find a 7912 for much under $700 nowadays. I've seen 1035's with endpieces fetching north of $500.
Here's a picture of my 105.003 ( fitted with a Pulsations bezel.... I too am looking for the "right one" )
All the Best
Steve