Hi Chris
I had to upspec my Tinka for my Vag and also went with the Hydrastar too. Simple easy to use and durable.
A range of controllers work them as opposed to some other types of brake set ups.
I had overide hydraulics already on the trailer so it was fairly simple to upspec the pull and fit the hydrastar and connect it into the hydraulic lines. Also it has a battery box that works it if the trailer takes off from the car.
The guy who did most of the work has a boat trailer building background and he lives up towards where you appear to be.
Cheers
Chimo