Anyone have experience using an Etang J-Head with an i2 Mendel

I bought a J-Head with fan mount from Etang => [www.ebay.co.uk]

only to discover that the fan mount means it won't fit on my printer. There is not enough room between the tracks / rods that the Wades Extruder is mounted on.

Two questions:

1. am I just unlucky in that my tracks are more narrow than normal (they are 42mm apart)?
2. has anyone else encountered this problem and if so do you know of a solution?

Many thanks.

James.

I measure the cold end and see if one of the shrouds fits [www.thingiverse.com] and grab a 30x30 fan of ebay £2.