From 1968, this is an advert from New Spotlight magazine for the Wimpy Restaurant (or Resturant even) at 50 Lr Dorset St, Dublin 1. This is just across the road from the Big Tree pub. (See location here from Google Street view)
Phil was 18 and still with Skid Row when this was taken. I think that is DJ & columnist Pat Egan sitting beside him in the photo. (update 17/2: it is Pat Egan along with John Farrell – see comment below from Brian)
There was a Wimpy in Dundalk too. I can still smell the onions sizzling away on the heated slab.