Sorry, I should have reported that I found the original item requested under this thread some time ago. The entry reads
Susannah Sophia Daughr. of James Austin, Sutler to the first Regt. of Foot Guards & Sophia his Wife Septemr. 2nd
The Christening register page is interesting, showing first, over 18 Sundays from 10 April to 12 August, ten christenings, so about one per fortnight, with no parental occupation given, presumably all permanent inhabitants of the parish; then there are 7 on 19 August, 2 on 26th, 3 on 2 September, so 12 in just 3 weeks; of these, the first on 2 Sept has no occupation given, so presumably a local, and the other 11 have army fathers (8 from 18th Regiment, 1 from 53rd, and 2 from the 1st Regt of Foot Guards). The army was clearly a recent arrival - it was stationed at Barham against the threat of invasion by Napoleon, who inspected his army at Boulogne on 15 August.
Finding James's occupation was very useful, as it led into his later career, ending as club keeper at the Guards Club from which he retired in 1822. I still know nothing definite about him from before 1804 or after 1822 - possibly 1827 as he's likely to be the Jas Austin witness at Susanna Sophia's wedding.