I think the fact that you've gone and spent some of your own cash (about 8,000USD after the course, flights, accomm and daily's), not small change by any stretch, shows any prospective employer that you are serious. It's easy to sit at home and take a year long, outdated, distance learning course that costs £600.
Regardless of the UK not licencing ops staff right now, the bulk of the knowledge you aquired in the US would stand to you in any ops room.
If you insist on landing your first job in the UK then you might be in for a wait. If personal circumstances allow then you should consider overseas posts as well to get that vital 'first foot' in the door.Keep an eye on the M.East / African and SE. Asian carriers.
A point worth noting on having the FAA licence in the UK and elsewhere... EasyJet used to send their ops staff to the US for FAA training, not sure which school they use though or if they still do. Also, KLM sends their people to Sheffield School in Ft Lauderdale and have had a long standing partnership with them.
Inspecthergadget is right, alot of ops bods are bitter n' twisted and stuck in a rut, going nowhere in a haze of never ending swing shifts for the past 20yrs. Not knowing what they don't know, they vent on pprune (just like the pilots) and are the worst ones to listen to.
You took a step in the right direction.
Best...
D.O.G