Postmarked in Foreign Offices Batavia

Thanks for your post, Roy (sudbury12000).

I think that paul1 may have a point about the date, but personally, I suspect 1st November may be it. In most cases where the month is in Roman numerals, the day number will have a serif in the font (or vice versa). Since both fonts are sans serif, I think the month is not a Roman numeral.

Just my opinion, and of course, others are welcome.

I am away on travel at the moment, but this coming weekend, I will check my Straits Settlements for other cancellations to see if I can find anything similar.

what I know about C19 issues in Java/Jakarta is not of help in this instance, but it does appear that after French ownership the British ruled from 1811 to 1816, then transferred control back to the Dutch in 1816, so a British P.O. in Batavia c. 1870s seems unlikely.

As for Chris' comments about serifed fonts, regret none of my few 'young head' Straits issues have a cancellation showing the digit 'one' with the clarity needed to resolve this question. However, have attached a picture showing three stamps of Ed. VII and George V issues where the digit 'one' is definitely a sans-serif face   -    but is it possible the following may help to answer the question.........

Having looked at a variety of British low values cancelled in areas like Penang or Singapore - albeit not 'young head' stamps - the date cancellations use typical letter abbreviations for the month (FE, MR, JLY),  similar to how they appear on the majority of British stamps cancelled overseas - unfortunately, the sequence of day and month isn't consistent  ......      rather than the typical format of C19 stamps issued by Continental countries, where the day and  month were mostly shown as digits.    
In the Batavia 8c. shown here, the date cancellation appears in the form of digits only - so, is it possible that despite this being a U.K. stamp the answer is it was simply cancelled in a non-British P.O., thereby acquiring a Continental style cancellation, and the part we see is typical for that period for a non-British cancellation - so my suggestion remains 1st February ....... or should that be January 2nd ;-).
Though I can't offer an explanation as to how this situation came about.

agree 1st November - and had I not been rushing that was what I should have corrected my earlier date suggestion to, and Alex's comment re the absence of a Br. PO in Batavia had already been established in earlier comments.
Do we know that this 8c. item was definitely cancelled on board a ship??