Peugeot Premiere- what headset to go for?

Hello everyone,

I need to replace the headset in my Peugeot. It's a 1 inch headset and I am fairly certain it has a 25tpi thread. Do I also need to measure the inner diameter of the headtube to buy the correct headset?

Once I identify the sizing, do you have any advice for a good value for money headset? I see they range in price from £10 to £50...

Thanks

Tange do good bang per buck headsets when you sort out the thread and stack height

Here's Sheldon's crib

https://www.sheldonbrown.com/cribsheet-headsets.html

Damn, I didn't even know what the stack height is. Thanks!

Looks like the thread is a 24, as it surely isn't a Raleigh headset.

Any reason not to go for a sealed bearings headset?
I like the idea of not having loose balls, and with the London weather, anything "sealed" is good, me thinks