It doesn't touch the oil cap on the M54 - it looks closer in the picture than it actually is - there's a good gap under there... I'd say it would fit over an N52, if you look at the photo above with the wooden pole - the oil cap is recessed and much lower on the N52...
Sorry everyone - I haven't been getting notifications for this thread... Yes, it is still available! I've sent PM's to everyone who has posted here, but in the interest of fairness, I have to offer it in the order of who posted first... 1. Mhc04, 2. GrahamA and then 3. Claret, I hope that's OK...
Doesn't look like I'm going to get a reply... I have read that; an M54 brace will fit over an N52, but it would block easy access to the oil filler cap...