I can't see why Ryanair guys would see this as a useful rating to invest in over their 738 ratings. Where the hell are you going to go with a 787 rating?
Thomson? Union
Virgin? Forget that unless you flew a fast pencil, wore badges and had a name like "badger"
BA? Tenuous reason to spend the money. May as well stay on the 738, you'd still be able to apply if you wanted.
The ME/FE/ rest of world etc? Just apply directly to these companies with 738 time if you are hell bent on leaving the UK. The ME etc are all taking non rated.