I wasn't aware that BMW produced a "high" seat, I know they did a normal and a low seat. Have your seats had extra padding added to make them "high" ?
BMW do three seats for the K1600 GTL, you just have to find them as I found some dealers simply do not know what they can and cannot get hold of.
The LOW seat is what it comes with from new and you can also get a HIGH and extra HIGH seat, all direct from BMW. The EXTRA HIGH is only available with a new bike, not as an aftermarket item bizarly enough. This one is a Genuine BMW HIGH seat from BMW with no alterations, but I do also have for sale a "Tony Archer" BMW low seat (the one the bike came with) which has been re filled/shaped and upholstered by Tony to be higher and wider than the BMW HIGH seat I have, so it's now like the EXTRA HIGH seat for BMW but obviously Tony has worked his magic on it and made it slightly softer, longer and wider.
James