Steve this is an agregious fake. They're all over the place, and they take in a lot of collectors. The biggest give-away is that the forger couldn't spell 'POSTAGE': have a look at the stamp.
This is what the real stamps look like:

(The fact that these are perforated makes no difference. The same rubber stamp was used for both.)
As these were more often used for revenue than postal purposes, you can also find genuine stamps with the fiscal cancels removed, and faked cancellations similar to that on your item.
Edit to add: The real stamp would be SG 29 (mine are SG 30), and 2012 catalogue value is £90. Actual value: nil, I'm afraid. All the Charkhari collectors have more than enough copies already.