Tips for buying a used bike

Buying second hand is a minefield, but the advice above regarding the use of a couple of well thought out questions is your best way of ensuring a bike is legit.
I bought a banger recently and restored it to a thing of beauty (still need to replace the rims and rebuild the wheels).
Bringing a good quality steel bike bike to life is an immensely satisfying exercise.

If you do buy an older Raleigh, be careful as they were such a huge organsition back in the day that they could afford to make a lot of their own components and as a result they aren't always compatible with off the shelf replacements now.  A good example is bottom brackets - Raleigh BB shell threads can have a different threads per inch (TPI) value than that used for current off the shelf replacements.  There are options but they do take more money or time to locate

Sorry to hear than Duncann, I've had a couple of bikes stolen in my time and it sucks. Though with a vintage steel bike, it's alot cheaper to replace than your generic carbon number. And harder to fence too so I would imagine less attractive to steal in the first place. Though I concede most bike thieves are less clued up about actual market value than the average club cyclist and will nick anything that isn't bolted down. That's why I never leave mine locked up on the street, ever. Unless I'm standing outside a pub watching it. Even then I use a hefty lock.

Having bought many a steel frame off ebay I would say you would have to be pretty unlucky to land a stolen one. As medic_ollie pointed out if they're selling components and frames and seem at least clued up about bikes then the probability is they're not a thief. Who would strip a whole bike to sell the frame for only a hundred quid or two?

I would certainly recommend you pursue your dream of recreating that magic with a proper vintage steel frame. I have a fair few which I ride - equipped with modern componentry such as Campag Chorus (all silver) or mix and match carbon and polished Record '04 10 spd which unless you're racing in Elite category road races are just as fast as a carbon superbike costing thousands. That is an arms race IMHO to be avoided. £3k on a superbike (fairly mid-range for that kind of money) is easily beaten by just over £1K in the style/ class/holding it's value stakes. Not to mention the real difference in a steel framed road bike is the magic ride feel you can only get with steel. That's worth more than £££. And at way less £££.

Turn up to the club run on a vintage DeRosa with modern campag and good wheels you get instant kudos. Turn up on an off the shelf  identikit bit of matt black carbon no one even notices. 

Basso are very undervalued steel frames at the moment. I bought an 80's vintage Loto (Columbus SLX tubing) frame for £61 a couple of years ago on ebay. Had it acid dipped to kill the bits of rust and sprayed it matt black myself. It looks killer with new transfers and Record Carbon 10. Rides better than my £3k Pinarello carbon did.

I would go for: Moser, Bottechia, Colnago Tecnos (lighter than the Master and way way cheaper), Battaglin, Rossin, anything with a decent heritage and a Columbus SL, SLX or above sticker (nothing against Reynolds 531 of course, I have one too). There are plenty of undervalued frames out there just waiting for a second life. 

https://checkthatbike.co.uk 

Great website for checking if the bicycle you're looking at has been reported as stolen.

If it's too good to be true then it probably is. 

I always ask sellers on eBay a couple of questions- if they're responsive and knowledgeable about what they're selling then you're probably going to be alright.

Also have a look on Facebook for local sale pages. There is a great one for the Southampton area- people are going to be less inclined to peddle stolen goods if it's less anonymous.

Hope you find your dream bike