I too have just done all 4 episodes.
I erred between disbelief, fewm and a lump in the throat. I didn't realise that 'Bob' was Ian Hart.
I doubted Bob in the beginning but he was great.
That scene around the table after "there's a pint of beer in Wales with my name on it"... it's in Beddgelert. Close to the Saracen's Head.