Couple of things
1. I don't think you'll have much luck with electoral rolls for the 1840s for Dowlais - you may have more luck looking up the rental records for the area (which I believe have been indexed by the GFHS). Probably best to email the library and ask them what they have to avoid disappointment
library.services@merthyr.gov.uk <library.services@merthyr.gov.uk> The library has loads of info and data and you could easily spend a day or 2 there! I don't know what specifically you'll be looking for at the records centre in Cardiff but to date, I have managed to find all the info I need about my Glam relatives at the library in Merthyr.
2. The Cemeteries department is only about 2 minutes walk from the library. They are
very helpful (as are the staff at the library). Some of the records are computerised but you may have to search through the actual registers themselves to find some of the info you are looking for. Best to have a list of potential names, dates and addresses (if you have them).
3. Should you need to get any certificates - the registrar is just across the road from the Cemeteries department (which is in the new Council building).
4. The Mormon centre is about 5 minutes drive away from the Town centre (if that!) and has plenty of parking. As advised by Ozlady, I would ring and book a visit as it gets very busy. Personally, I only use the Mormon Centre to order films for outside the Glam area as the library probably holds more info about Glam.
Official opening times are
M-W 2pm-5pm; T 10am-1pm; F 2.3pm-5pm; T, Th, F 6.30pm-9pm; W 7pm-9pm
They are based at the Church of Latter Day Saints, Nantygwenith Street, Mid Glamorgan, Merthyr, WALES - Tel: 01685-722455
Personally, I would recommend a stay over in Merthyr to investigate the library and the Cemeteries department before deciding if you need to go to the record centre in Cardiff.
If you do decide to go both locations in the same trip, Merthyr is about 24 miles from Cardiff - up the A470 which can be very busy particularly between 8am-10am & 3:30pm and 7pm - so if driving between Merthyr & Cardiff I would take this into consideration as it could "eat into" the amount of time you can spend at each place.
By far the easiest place to stay in Merthyr is
http://www.castlehotelwales.com/home.htmlIt's opposite the Council Building (where the Cemeteries department is situated) - the Registrars office is in the same buidling just around the corner from the hotel main entrance and the library is about a minutes walk away!
If there's no room there - I'd recommend
http://www.tregennahotel.co.uk/Still within walking distance but situated at the "other end" of town.
Hope this is of help
