Thanks to everyone for your positive responses.
I would honestly say that in Welsh speaking areas the people are as patient with learners as the first language speakers that I know in my hometown in the valleys.
The areas that I visited are all popular tourist areas and as such have many, many different nationalities visiting, including lots of Welsh speaking people from all around Wales. No matter what version or dialect you speak, they will understand you - just as they go visiting other parts of Wales and are understood just as well. Welsh speakers from non-tourist areas go on holiday, visiting etc. around Wales so they too are exposed to and understand whatever Welsh is used. I deliberately went out of my way to test this theory by using south Wales constructions in north Wales and to try out pysgod a sglodion v ffish a tsips. Ffish a tsips, from what I have read, is more popularly used but as stated an eyelid wasn't batted when I used pysgod a sglodion.
No-one questioned my Welsh, indeed the only question I was asked (by 2 people) when I spoke Welsh was 'Where are you from?' because they didn't recognise my accent. They recognised I was from south Wales but couldn't pin down exactly where from.
I've only been learning for 2 years and had absolutely no intention of learning any north Welsh but you can't help but pick up and remember some of it subconciously, so when I was asked in Machynlleth 'O
lle wyt ti'n dod' I had to ask the lady to repeat what she had said; when she did, a litttle wire connected in my brain and remembered 'oh yeah, they say
lle here not
ble as I would have said. Although it seemed a stupid question for me to ask I couldn't resist coming back with 'O
ble wyt ti'n dod', the lady grinned as if she knew what I was doing and just answered 'Machynlleth'.
The only disappointment on my travels was that ALL the bar staff, shopkeepers, hotel staff etc. would speak to me in English first. On my first night, which was in Ynys Môn, I was spoken to, in English, by the girl serving behind the bar, I strongly suspected that she spoke Welsh so just asked her in Welsh ‘Wyt ti’n siarad yn y Gymraeg?’ she flashed a big smile and answered ‘Ydw’ and never spoke to me in English again. She went on to explain that they have so many visitors of differing nationalities who can all speak at least some English that she finds herself automatically speaking in English to people she doesn’t know. Armed with that information, from then on, whenever a shopkeeper, bar/hotel staff etc. spoke to me in English I would just answer in Welsh - you'd have thought it was my first language

. Only twice did I come across a person who did not speak Welsh, they were both shopkeepers; one in Betws y Coed and the other in Tyddewi.
As a very proud Cymro you can’t believe just how wonderful it is to, at last, be able to speak my mother tongue, yr hen iaith, in my own country – and be understood.
Rygbigal:
To answer your question, in Tyddewi I came across a lot of first language Welsh speakers, a learner (working in a shop) – she was more nervous about speaking Welsh than I was! But also a shopkeeper who couldn’t speak any Welsh; so quite a variety – but then that’s life, hey?