Not before time, Ancestry has released the remaining 'Burnt Documents' and these are now searchable - after a struggle - on the Ancestry site. It's a pity, having waited so long for these, that Ancestry seems to have completely messed up the search function. Type the first name and surname in the relevant boxes and you'll just as likely get no results. Type the same names in the keywords boxes and the results appear.
Similarly, it's no use typing in the regiment (in the regiment box) and the name (in the keywords box) at the same time. That will also get you no results. Type the names first, wait for the results, and then narrow down by regiment. The information is there, it's just that Ancestry has messed up the search.
In any event, apart from finding my great grandfather's service records, I've also had a quick look at some of Chailey's men and found records for the following:
Francis George Pettet
There may be others, but in the meantime, I'll be updating these men's pages as and when.