Being from Ireland too, I know the boat you're in. I live in the US now, but I remember how hard it is to get many of the sundries we take for granted in the US (such as exotic leaves, etc). There simply isn't the market to support it in the British Isles.
You've got a few options though. You can still use local deciduous leaf litter. It will rot much faster, but it will work. You'll just have to change it out regularly. I suggest you collect some bags of it asap and dry the leaves out so you can have a supply throughout the year until next Autumn. I would try to use oak over something like chestnut, beech, sycamore or rowan, for example, because it ought to last slightly longer. If you're really lucky, you might have some local magnolia trees. The fleshier the leaf the better (there are different kinds of magnolia, and US Southern Magnolia can survive in Ireland). Even normal magnolia will outlast all of the other trees I've mentioned.
Option number 2 is to order some from England. It won't be cheap though, and the big dart frog vendor there (I would mention the name as I'm sure a mod here would censor it *facepalm*) knows how to charge.
Option number 3, and this is my recommendation, is to order it from a vendor in the US, or even a hobbyist. Get a big dose of southern magnolia leaves and some live oak leaves. There should be no border issues - it's a long dead plant, and the shipping weight shouldn't be too bad. From a customs point of view, provided the declared value is low (hey, they're leaves, how much are they really worth?), you'll have no issues. This option is probably not worth it if you're not planning on getting too big into the hobby.
The leaves are dry and last for years in bags, so you could get a couple of years worth of leaves for, in the long run, a heck of a lot less than it will cost you to order them from England.
Anyhow, there are some ideas to play with. Send me a PM through the forum if you want to talk more. Are you getting your imitators from Ben Lyons? Do you know him? He's the Reptile Haven guy and a long time friend of mine.
