You could try giving SJS a ring and see if they'll send one to you in Ireland (with a bit of extra postage money). They might well oblige. Otherwise get it sent to a kindly aunt or someone in the UK, and get them to forward it. Failing all that, I don't mind forwarding one to you. Too good an offer to miss!
I know what you mean about over-insurance. To my mind it's about weighing up the probabilities of something going wrong, and the consequences if it does. And I'm convinced that with racks it's false economy to buy low to mid-range for this type of expedition. Cheap racks aren't made for carrying tons of stuff for multiple thousands of kilometres. In my opinion there's a strong chance you'd break a low quality £20-£30 effort even on the 'least demanding' silk road route (Iran/Turkmenistan/Eastern Uzbekistan/main sealed road around Kyrgystan). Throw in a few detours (stunning central Kyrgyzstan, Tajikistan, etc...) and I'd give you 10-1 on that a budget rack would break. Last time I checked, there were just a couple of reasonable bike shops in Iran, and none at all in Uzbekistan or Kyrgyzstan (save for a couple of market stalls selling bells that don't ring and puncture kits that don't stick). That was three years ago...I doubt things have changed much. I actually crossed Uzbekistan rather than Iran, and didn't pass a single bike shop between Ankara (Turkey) and Kashgar (China)(!). Basically unless you were in Iran you'd almost certainly have to get one sent out, which would be very expensive and eat into your precious visa time.
But then of course fortune favours the brave and all that. I hadn't seen those jubilee clips- maybe they'd hold for a while. Very much a temporary fix though, I'm sure. Probably better than the stack of zip ties I used to bodge together my Blackburn mind you (which lasted all of 10 miles).
Er, any joy with the front racks yet? I don't know what to suggest really, other than checking Ebay for a 2nd hand Tubus. Used Thorn fronts never seem to come up. Worth checking ebay.de for Tubus- they're popular over there and you might get a better price.