Peugeots sometimes have odd sized tubes - seat posts are a nightmare to find for them, and the threads are french-threaded.
Raleighs might be Raleigh-threaded. (when they were the largest factory in the world they didn't need to bother with standards.)
Both of these are a pain in the arse to get bits for. British or Italian thread is much easier.
There is a thread which is a list of tyres. There are similar lists of other components.
To be honest you can build a very nice bike for £500.
Peugeots sometimes have odd sized tubes - seat posts are a nightmare to find for them, and the threads are french-threaded.
Raleighs might be Raleigh-threaded. (when they were the largest factory in the world they didn't need to bother with standards.)
Both of these are a pain in the arse to get bits for. British or Italian thread is much easier.
There is a thread which is a list of tyres. There are similar lists of other components.
To be honest you can build a very nice bike for £500.