zOwie Omega Discussion Forum

I'm looking into getting a vintage Omega, and have mostly been looking online.

One site that had a few I like is Gisbert Joseph, and when I researched it when mentioned in forums etc it seemed to be regarded as reliable.
However I have 2 queries about it:

1) I might just be being stupid and using the wrong numbers, but when I put in what I think is the reference number, of the Cal. numbers into the Omega vintage watch section, the watches that come up don't seem to be the same as the ones I'm looking at. They are always from a very similar period (Off by up to 4 or 5 years usually) and have a differernt dial and sometimes different shape. I'm looking at watches from the late 40's or 50's so I don't know if the records aren't as good, or whether Gisbert Joseph is giving dodgy numbers?
I don't want to be stuck with a fake one.

2) They seem to be quite expensive when compared to similar watches I've seen on other websites; the other ones usually appear to be in a worse condition in terms of dial etc but I don't know if its enough to justify the price difference (sometimes up to 150 GPB or so).

Does anyone know if it is a genuinely reliable site, and if its only a little overpriced (which I am happy to pay for the peace of mind) or a rip off?

I don't know if you're allowed to post links to sites so I won't, but I'm looking at Omegas in the 500-800 Euro range (It's a spanish) site from the 40's or 50's. If there is somewhere else I should be looking I would be grateful if you could let me know; I intend to look at some actual shops in London at the weekend but I'm not sure as to their reliability either (there's one authorised vintage omega dealer in London now but I suspect the prices will be astronomical).