Are flip saddle posts available When trying out the baby seat on my wife's e-bike, it was really easy to fit and remove because her saddle flips up to access the battery.  It's a real pain threading the baby seat over the top of my pannier(s) and under the saddle to fit it on my bike.

FWIW the baby seat is a hamax siesta, seat tube mounted, and slightly fiddly to fit even with rack but no panniers. I can't fit the seat then the panniers - there's no access to fasten the panniers.

So is there a flip-up seat post available to fit to a normal bike?  Google finds nothing relevant, only ancient forum threads.

Edit: Pics

Here it is flipped up:


And in riding position:


Detail of the mechanism:


As you can see the standard QR height adjustment is unaffected, and the saddle rails are typical.

I've found out a bit more - apparently there's quite a bit of extra weight (looks like it, plenty of steel in there) and older versions had a tendency to work loose around the hinge.
Answering for completeness:

Such saddles are available but only as spares for E-bikes, from the bike manufacturers.  They aren't necessarily compatible with a normal saddle as they use unusual mountings, and the saddle post diameter isn't specified (instead they list which bikes it's a spare for).

They're heavy and not necessarily designed for hard use.