It's the factory front sight at the moment - will this still have a height marking on it? (I'll check when I get home tonight, I have to do bore copper removal part 2 anyway). The heights of the Recknagels are measured from the bottom of the dovetail? (the link to their catalogue on their website doesn't seem to be working at the moment)

I have Graeme's response already. He's indicted (this is a partial quote) that I'll need to get an order in shortly as DHL (handle all parcel post out of Germnay) are not going to deliver guns or gun parts after 1 July and that he will not going be able to get Customs clearances for shipments after the middle of the month.