https://www.ebay.co.uk/itm/Marlboro-Oly ... Sw9RdbCYqcI can see one Marlboro frame on EBay at the moment linked above This one is a 24” frame, so would suit a taller rider, say around the 6” mark. The asking price is fair for what’s on offer there, but the postage is inflated.
If you’re going the vintage route, you ideally want to be paying around the £100 mark total for something made from Reynolds 531 as much as possible and that will be the right size for the rider. The more prestigious the brand, the higher the price gets. All the brands you mention are OK and won’t come in too expensive. Dawes and Raleigh are historic brands in the UK we’ll thought of by tourers so you’ll meet frames of varying ages. I’m less sure about Carrera and Merida - you may get more modern products there.
If you look at the £300+ frames, you’re getting 531 throughout - main tubes, rear triangle and forks, the name, state of condition, branded dropouts (where the wheels fasten), the rear brake doesn’t just go in a hole cut in a tube, there’s a proper housing, lugs where used (i.e. the joints) will be a bit decorative and above the norm, and they may be lined in a contrast colour.
You want a frame that hasn’t been bashed or bent. A couple of minor dings on the tubes are tolerable, but holes and cracks are not for your purposes.
I’ve restored several 531 frames dating from the 1970s, 80s and 90s. You need to know how much restoring and adjustment your boyfriend is prepared to do. A 1990s frame should be ready to build up, while older frames may need the rear drop out widening and may lack cable stops or bosses on the downtube. The rear dropouts need to be 130mm apart to run modern wheels and gears. If he’s happy to run downtube levers as many tourers do, then lack of bosses is not a problem.
Most frames you’ll see for sale will have mudguard/rack eyes, but check. Older frames may not be compatible with modern brakes that use a recessed nut - you can run nutted brakes or widen the holes for the brakes to 8mm.
Older frames will often have been designed for 27” wheels and the standard has been 700C wheels for many years - this makes a difference to the “reach” of the brakes, where it’s a factor - but he’ll be able to work this out in the build process. Seat posts are sized in steps of 0.2mm with 27.2 mm being the most common. My point here is that I haven’t found a definitive way of measuring these - it seems to be “suck it and see.”
Another factor is whether he’s happy with the paintwork - the Marlboro looks OK. Proper bike painting isn’t cheap or quick and I don’t think is economic - unless you’re an enthusiast. You can get by with powder coating if it’s a nice frame in poor nick, but any refinishing loses the bike’s character. You can get replacement decals for many makes and models.
The Marlboro includes a head bearing so that’s one less item to worry about assuming it runs smooth and there’s no play in it. You won’t normally get a bottom bracket bearing - just make sure the b/b threads are OK. They’ll almost certainly be English/BSA standard, but check.
Some vendors’ descriptions are clearer than others, but I hope i’ve given you some idea of the things you need to know from them. If I was selling I’d want the world to immediately see my 531 decals on the frame and the forks, complete with the nicks and scratches that befit the age.
I did do a post on here a few weeks ago looking at the cheapest range of decent new components built to a cheap new aluminium frame - I think it came in at just over £600. Places like Ribble and Planet X do new frames for not much more than you can pay for 531 vintage on Ebay, but these tend to be racier than perhaps your Bf is looking for.
A lot to think about in terms of second-hand steel frames. I don’t disagree with earlier posters about how you should approach this, but if this information helps you talk in more depth about your Bf’s (other) passion then I predict a happy future for you!
my boyfriend is a bit of a bike geek and I worry I’ll accidentally buy him a bike that is ‘uncool’ in bike circles or something.
