Charlie, if the bracket is not removed and the frame restored to stock, there is likely to be future regret when for the next ten years, knowledgeable Ariel owners will be asking WTH whenever you display your machine.
I very recently restored a rigid frame. I spent hours in repairs and metal finishing before I sand blasted it with 80 grit oxide.
Be aware that grease will leak out of the steering head if the grease is not thoroughly removed before going into a powder coat oven. Mine leaked out the bottom of the Center vertical tube but did not affect the paint.
I also spent time creating protection for the bearing races using ready rod and washers.
I was charged $150.00 for the powder coat. If you have silicone plugs inserted it all screw holes and bolt holes charge out fees will be reduced and it will save a lot of time filing out paint and chasing threads.
After this advice you may opt for a rattle can