It all depends on what you like. There were hundreds of different styles made during the hey day of dip pens. I'm assuming you want a pointed pen. If you're looking for new, then Honeybadger's suggestion is a good one. If vintage, then there are a lot of different ones to choose from. You're in dip pen paradise there in England. More pens were made in Birmingham than anywhere else in the world, by far. And there are a lot still around to choose from.
If you had a choice, and you're just looking for a pen which is easy to write with, I would find a William Mitchell "Fine" "J Pen". The "J Pen" (and everyone made their own version, I just happen to like William Mitchell's the best, though Geo. Hughes made a nice one) was the best selling pen style in England, outside of maybe Gillott's 303. The Medium ones, I find a little large for regular writing, but then I write rather small. If you're a large writer, medium will work.
Look for any of the shoulder pens. They make great every-day writers. I like the Birmingham Education nibs that show up fairly regularly, and inexpensively, on the auction site. If you want no flex, then look for a Manifold pen. They were stiff enough to write through sheets of carbon paper, but their tips were also finished to be smooth since you're putting more pressure on the pen. It's basically a nail, but smooth.
Post Office pens were also meant for lots of different kinds of people to write with, so they are not too flexible, and fairly robust. Also any "spoon" pen or falcon pen is meant to be an everyday writer and should work well.
You can visit my glossary of pen shapes to know what I'm talking about with these shape names. https://thesteelpen....posed-glossary/
Unless of course, you're looking for a stub. Then you have to go vintage. Pretty much any of the vintage stubs will be great. They were originally invented to be smooth and to facilitate rapid and continuous writing. I'm particularly fond of the Esterbrook 314, which was made both in the US and in England.
If you show an example of the kind of writing you do now, and if you have had a vintage nib you've liked, I can get very specific for vintage nibs. Modern nibs are more limited in what's available, and the Zebra G is probably the best all-around pen made now.
Glad to hear someone else uses dip nibs for everyday writing. Most of my collection and knowledge is focused on American dip pens, but you can hardly be completely ignorant of British pens if you study this subject for long.