I would consider AKK FX3,it’s 5.8Ghz,40CH,25mW/200mW/400mW/600mW power switchable,this company is doing great .
I understand this is a fully UK/EU based forum, but just for those that are googling and come across this, the U.S. does allow Amateur Radio, or HAM radio, to be used for RC vehicles. But its more always been in use with fueled engine planes, not Quads and other forms of drone.
Using that high power of a system is extremely overkill with Quads, even those with the best of battery. However, more and more people are looking into using them with medium to large scale RC planes, which often have flight times measured in hours.
