If you look at Google maps, you will see how close Tirley and Deerhurst are to the water.

I've checked my Gloucestershire CD's for burials/births of COLLIER - parents Thomas & Ann(e) - and can't find any that are appropriate - as there is only one child listed O/Austin on the 1841 age 2 - and this couple married in 1832 - so the Wiltshire Indexs' are worth checking.