Seahorse Neat Cancel Or Not?

scb, Thank you very much for your kind answer! :)

The block cancels that I assumed to be revenue might not be just because the stamps are only marked "POSTAGE". So assuming the ones that are marked "Postage & Revenue" can be used both ways and the ones marked Postage can only be used for postage, the stamps can not have revenue cancels. That being said, there are several examples of Revenue stamps being valid for postage - the KGV Bermuda 12/6, KGVI Ceylon 10R and KGVI Hong Kong 5c all come to mind.
I still don't find the block cancels to be collectable and would still not be interested in purchasing them.
Gibbons states that used stamp prices are only for those showing postal use - but if they were never used for revenue - what else would they be used for? Unfortunately Gibbons doesn't elaborate.
Has anyone seen any websites elaborating on the various cancellations used on the Seahorses?

"POSTAGE" inscription or not, Seahorses were used fiscally, and used that way often enough. An example:


But postage/revenue use gets even more complicated. You may have seen £1 Victoria or Edward VII stamps each with a neatly struck socked-on-the-nose Guernsey or Jersey CDSs (both might exist, not sure at the moment). These are genuine usages. However, postage and revenue/fiscal fees were paid with the one stamp, with the fiscal charges far exceeding the cost of postage. They are collected as postally used. These are not to be confused with the forged £1 Edward VII "postmarked" from the Channel Islands.

This one is a Bradbury & Wilkinson print 1918. (some type of oval registry cancel)

Sorry, but the blue-violet color of the oval cancel says this is a revenue cancel. The postal registry ovals of the period were always in black ink, somewhat smaller and did not have three rings but only one outer ring.

Nice stamp. I'd own it. (But I collect revenues, too.) I agree that that has all the hallmarks of revenue usage. Still appealing.

I'm not sure whether anyone's mentioned this yet but the original picture shows it's from the earlier issue of the Seahorses, not the later 1930s issue that probably would go for a couple of pounds each.