Hi Stewart,
I found a great grandfather living a 'C Pit Cottages', Llanelli. This turned out to be cottages attached to the former St.David's Pit at Llangennech on the outskirts of Llanelli. I can't tell from the census extract you've put up if it's the same in your case, but it looks likely.
Llanelli has also been spelt Llanelly at times, so don't let it cause too much confusion. There is another Lanelli as correctly pointed out, but if you check what county this census entry is listed under it should help establish the correct Llanelly!
Can you (or anyone) give us some more info, I've not got access to the census at the moment. I managed to find the location of St.Davids Pit after trawing over a few old maps, I'd be glad to share this with you if it the same place.
Regards,
Buckaroo