That's a decision only you can make .
My advice would be to try and aim for a bike made by a smaller brand name as you are hopefully going to get a much better quality of bike although there is nothing wrong with the more mass produced bikes like the Raleigh you have been looking at .
There are some bargains out there just keep looking would be my advice .
If you are considering having what ever you buy restored then it will get expensive , i prefer patina over new paint sparkle all day long
If you were more local to Northamptonshire then i was going to say you are always welcome to have a wander round the biggs garage and try a few steel classics