Hi Down There,
has our heavy rainfall seeped thro' to cool you yet ?

You do ask some challenging questions don't you ! ;-)
I'm afraid I haven't a clue, I'm sure one of the Admin's does tho.

My first thought was Gloster Archives, in what I call their "non-Conformists" site.
However that doesnt seem to recognise Parkend as a Parish, unless it's included within "West Dean" perhaps ?, so ??
Suggest you try it anyhow tho' just in case.
http://ww3.gloucestershire.gov.uk/genealogy/Search.aspx

The Glos Archives do have a file of the Chapel's general accounts etc, but no mention of the Registers; this found from a National Archives site link.
http://ww3.gloucestershire.gov.uk/DServe/dserve.exe?&dsqIni=Dserve.ini&dsqApp=A...

No mention on Parkend Baptists on GlosBMD site.
http://ww3.gloucestershire.gov.uk/bmd/Progress.aspx

So, in short, sorry but I don't know ?
J