The Gehmann butt plates are more reasonably priced compared to the MEC. And the british pound is currently very strong against the euro. Buying in Germany may give you a good deal.
Or do a search with the German words: "alu schaftkappe" to find an even better price: https://www.google.nl/search?q=alu+s...AQsAQ#imgdii=_
You may also try on the German auction site www.Egun.de
and do a search for "alu schaftkappe" there. (you can even find unused LGM-2 stocks there for 125 euro if you'd like to replace the current stock http://egun.de/market/item.php?id=5344235