I've seen the photos you've posted of some of your work Billy, it's impressive stuff and you're definitely ready to vanquish the dovetail bogie man and move a couple of rungs up the skills ladder!
Yes, you absolutely should practise on scrap first. But here's a suggestion for a first project.
The first dovetails that apprentices at the Barnsley Workshops cut are pairs of Book Ends, these are about 12mm thick, 125mm wide, and the upright is about 200mm tall with a curved top. You start with rough sawn boards and absolutely everything is done with hand tools.
Work with a board longer than necessary, so if you make a cock-up you just cut off the offending joint and start again. After doing lots of these and hitting the target time for making them, apprentices then move on to the same thing but with mitred corners. After that comes a "practise drawer" made to the best arts & crafts standards, and then you're considered ready to dovetail on actual furniture.
Now here's the really critical thing about dovetailing that hardly ever gets mentioned. It's much, much harder to dovetail neatly and accurately if the board is even fractionally out of true. For someone in a well equipped workshop with a good quality planer/thicknesser and an accurate cross cut saw that's not an issue. But for many people the real challenge in cutting dovetails isn't the actual joinery itself, it's starting with perfectly square and true timber. You say you're in Southern England, if you're anywhere near the New Forest you're welcome to drop by my workshop and pick up some straight grained stuff from the off-cuts pile that I'll machine perfectly true to give you the best possible chance of success.
One other thing, the Book Ends shown above are in Oak, that's not actually the easiest dovetailing timber choice for a beginner because it doesn't take or show layout lines particularly clearly. A slightly softer and closer grained timber like Cherry or Sycamore are kinder alternatives for a first attempt.
Good luck!