The problem with an L bracket is the MkI would then stick out of the MkII sled.

Of course it occurs to me that the MkI sled must have some antenna connector on it, so I'll need to get bits for that, too, and not just the (annoyingly expensive for just a connector) RP16. Tempting to replace the connector on the MkI, but then it wouldn't be original. Bah.