Hi Vanda
These are the only ones that seem to fit the bill (but don't take my word for it, wouldnt want you going down the wrong track - keep an open mind

Llanallgo SH5085 Anglesey
Llanddewi SS4689 Glamorgan
Llanddwywe SH5822 Merioneth
Llandeglau SO1362 Radnorshire
Llandeilo SN6222 Carmarthenshire
Llandevaud ST4090 Monmouthshire
Llandilo SN1027 Pembrokeshire
Lland-lwy SM8526 Pembrokeshire
Llandrillo SJ0337 Merioneth
Llandudwg SS8578 Glamorgan
Llangeitho SN6159 Cardiganshire
Llanelieu SO1834 Brecknockshire
Llaneuddog SH4688 Anglesey
Llangwyryddon SN5970 Cardiganshire
Llanwyddelan SJ0801 Montgomeryshire
Falkryn's Llangeitho look's favourite but some of the others are in with a chance, particularly the Anglesey ones. If any Welsh speakers could eliminate the rest on pronunciation compared to the enumerators phonetics we might narrow the search, might be worth a request to the welsh speakers site.
Cheers
Tony