Rod, the CANCELLED cancellation points unerringly to a fiscal use. Those very attractive Pictorials
without overprint are from a series of Revenue stamps issued in 1933-34, well before Bahawalpur was authorised to issue postage stamps.
Your 1½ Anna surcharge used is one of the exceptions to the general rule on Bahawalpur stamps, that used and covers are to be regarded as iffy. Here is the complete set of surcharges:

However, this set
used, say, is to be avoided. There's quite an industry in providing fake cancellations on Bahawalpur. (If I was in the market for them, and I'm not, I'd go for slogan cancellations or messy-looking CDSs, with a definite and appropriate year of use visible.)
Not that I shun fiscal uses - far from it. Postal-fiscals used as fiscals on document, I quite like. I recently picked up this copy of the 1921 Charkhari State 1 Anna (SG 29) on document, and with a punch hole:
