There are two battalions represented here, with two sets of colours at the back of the group. Alternatively, the ceremony shown in the upper 'wide shot' might have been the presentation of new colours to a single battalion. There is a group of people, obscured by the perspex ruler, which could be masking a drum head altar. (Intriguingly, it seems that some of our light-suited friends from the lower photo might be in that group).
There are 22 officers present that I can count. That would suggest only one battalion is present. Five are wearing a single medal, which might offer a clue, and suggests that these are regulars after all
Otherwise the two sets of colours might represent two battalions of the same regiment. The tunics have the same dark facings. Yellow facings that have come out black due to photographic process of the day, cannot be ruled out but I am not sure what to make of the shade of the regimental colours, which would be of the facing colour. Oddly there seems to be only one Union flag Queen's Colour visible, but that must be a trick of the light and the way the other Queen's colour is folded.
It's worth observing perhaps that the collar dogs do not seem to be identical in form on every officer. However, given the resolution, that can hardly be relied on. As Stuart says, a better resolution image will help narrow down the possibilities.