There doesn’t appear to be much available in the way of records at all and some are spread across departments.
In the 3rd & 5th paragraphs of the last section at http://discovery.nationalarchives.gov.uk/SearchUI/Details?ur...
there’s some background about how the Ordnance Medical Dept became part of the Army Medical Board in 1855 and from 1857 to 1870 there was a separate Purveyor's Department.
Then selecting the advanced search at http://discovery.nationalarchives.gov.uk/SearchUI
for Purveyor's Department dates 1850 –1870, you’ll see most are organisational records or statistics, with a few examples for individuals created from other documents.
They are included in other records that are free to download, but I have not checked the content; the fact they’re free could be an indicator of how few there are.
It’s even worse for a search for Army Medical Board, but truncating it to Army Medical gives over 300 returns but can be reduced by adding Department.
There are some items for individuals but watch for records covering dates that include WWI (picked by early dates), some are free some carry a nominal fee.
You have better luck searching for name.
Looks like army officers or SNCOs filled some posts, so it may be worth checking army officers' and soldiers' records see the relevant guides at http://www.nationalarchives.gov.uk/records/atoz/a.htm