I was quoted this price for a H1612 back in Jan of this year when I emailed them, they never told me that they only service and would not supply? It is likely that there has been a price increase since then.
You could also try Rick from audio Images in Sheffield, he is on this forum as well.

Since the drop in replacements are no longer available new its worth noting that the if the original H539's are replaced by black tweeters the sensitivity will need to be adjusted in config mode.The H1612 frequency response does not match the original above 10Khz.

The alternative is buy used or attempt a ferrofluid replacement if they have gone soft.

Rgds
Stuart

Linn LP12, Ittok LV11, Arkiv, Linn Kairn as a phono stage, MPmax 221, DSP6000's, WiiM Pro streamer.