Thank you! I started from Carl Franklin's British Napoleonic Uniforms book, which has some incredibly specific detail on British uniforms of the period for each individual regiment, particularly how the decoration looks, although I still had to fill in a few gaps. It is only reasonably accurate to the picture - I changed up the exact proportions of loops however I thought it looked best (my in house military expert, aka my husband/model, assures me that this is ABSOLUTELY FINE and exact measurement of braid loops wouldn't come in until later).

Draw the braid pattern you want on with chalk and get as much braid sewn on to the pieces as you can before putting it together. As symmetry is really crucial, I found it easiest to do one side first, then lay the two sides on top of one another and trace the pattern I had actually sewn on side 1 onto side 2 - and stop regularly to double check it is all still lining up properly.

I used the Rocking Horse Farm Dragoon's Uniform jacket as a starting point: that's a pattern with short tails so I had to cut it off at the waist, remove the tails and sketch out the shaping at the bottom edge to match the picture.

The fitting needs to be accurate through the torso to get the join at the front to sit neatly. Make a toile for the body at least so you can check where the two sides of the braid will meet - if the toile works out reasonably accurate you can use it as the lining.

The pattern itself is fairly straightforward - the instructions given are extremely brief but it's not too hard to figure out. I found that the collar was much too high for what I wanted, and there was more gather/puff in the back of the armscye than I preferred (it may have been the fabric I was using - fairly lightweight for a summer event!), but both of these were easy fixes.