Hi Alison4164,
Sorry it took me so long to do this look up for you, I have been very busy of late.
Right, there is one possible candidate for you burial
Patrick HURLY
Buried: 06 May 1847
Residence: Caedraw
Age: 41
St Tydfil's Burial Ground
I realise this this outside the time scale you mentioned but I thought I would let you know about it anyway.
I checked the two Catholic Churches burials, to no avail. Firstly, because St Mary's (Merthyr) kept no burial records for this period. So he might have been buried there, but there is no way of finding out. St Illtyd's (Dowlais) only has records from 1857 onwards, but he is not mentioned in the records after this date.
The two municple cemeteries open in Merthyr during the period. Pant in 1860 and Cefn in 1859. The good news is the the council has an index from which they are willing to do free look ups. The number you need to call is 01685 725415.