Remember buying from an authorised source means that the prices are fixed in GBP (no gambling on fluctuating currency exchange rates), import duty and import VAT has been paid (no need to take the risk with "gift" or reduced value invoices, the price you see is what you pay, and of course you are guaranteed to receive only genuine Mugen products.
FK2 prices here: http://mugeneuro.com/wp-content/uploads ... 16-FK2.pdf