Lloc has me a bit stumped in that there are two possible sites. I'm wondering if the Little Chef may have been on the north east side of the junction where McDonalds is now. Either that or, like you say it's the Cafe on the south west side.
old-maps.co.uk shows no building on the NE corner of the junction except for the Singing Kettle, which was a bit further east. It's shown by name on the maps from 1964, 1965 and 1969, and as "PH" on the 1992 map. It was still open when the Holywell bypass and GSJ opened but may not have lasted much longer. I think it more likely that the Little Chef was on the opposite corner, and may have been in the building that still exists. I think I may have visited it once or twice.
I think I've found 82 Bodelwyddan too. I've since got another old map from 1972 that calls it Kinmel Park. If you go to LL18 5SR on streetview and go to the entrance of Kinmel Park golf club on St Asaph Road(just to the north of the current eastbound Kinmel Park services on the A55) there's a bungalow-type building called "Spice of India". Just on the roadside, at the west side of building is the skeleton of a totem sign (with a Spice of India insert) which looks suspiciously like an old Little Chef one. I think this must be where it was.
You're probably right about that. I'm investigating and may post more later.