Obsolete tyre size?

[thirdcrank]

On that basis, if you want to use the existing wheels, any replacements must include the 630 number. The cheaper stuff you see in Halfords, Wiklinsons etc designed just to keep an older bike on the road is more likely to be 630 x 32 which is a bit fatter. Unless your mudguards are close to the tyres or your wheels are a bit wobbly, they should be OK.

As far as the shop goes that advised you, it's possible they were saying "We don't stock them" which is fair enough. If they really said that they were no longer available, they are either badly informed or economical with the truth.

[Tonyf33]

If you just want a cheap set, Wilkinsons of all places stock 27 x 1 1/4" tyres.

Terrible tyres, even though they are £5 or £6 just not worth it...really especially when Chain Reaction do the Michelin World tour for £6!

[belgiangoth]

On closer inspection both tyres are marked 27 x 1 1/8 and one also has 28-630 & my Carlton is nearer 25 years old when I thought about it - bought around 1983/4! It's great that there's such a wealth of knowledge out there! Thanks everyone for all your help & useful links to further info & suppliers.

Drat! I have an old bike with 26*1&1/4 which is a marginally bigger size than 26*1&3/8 - would have bought your old wheels off you.
27" tyres are still available, not in the same range as 622s, but a good selection is available. You could eventually go from 27" to 622s (aka 700c to bike shops not speaking ISO) which would allow you a wider tyre range and you could run fatter tyres for more comfort! IMO your old Carlton will be a much better bike than a modern bike, especially comparing the cost of an upgrade vs a whole new bike.