Looking at a photo of Ingledene's frontage, the ground and second floors have large bay windows, and there is a smaller window under the gable end, at second floor level. This strongly suggests that Ingledene did indeed have an attic, but Alfie is quite correct when he recalls the current owner posting on this Forum that the bathroom was on the first floor. So where in fact was/is the bathroom? First floor or attic? Or were/are there two bathrooms at Ingledene?
In Nick's clipping there is mention of a suggestion that Hanratty might have used certain features of Terry Evans' house, including a green bath, when he constructed his description of the Rhyl B&B he claimed to have stayed in.
We are suffering from a plethora of surmise, conjecture and hypothesis. - Sherlock Holmes, The Adventure Of Silver Blaze
It is the smaller window at second floor level. The current owner regarded it as more accurately described as being on the second floor rather than in the attic.
In the Daily Post (linked to below) you can see how Ingledene looked at the time, but cutting off just below the green bathroom. Notice it says 'Ingledene' in big letters above the front door. If Hanratty had stayed there this would have been one of the features which would have enabled him to return there on his second night.
The skylight in the roof of Ingledene belonged to the bathroom which housed the famous green bath. I think that this could fairly be described as an attic room. As far as I can recall this was the only bathroom, but there was a WC room on the first floor.
I wonder how Mrs Grace Jones would have faired in Four in a Bed, no en-suite and one toilet shared by all the guests and permanent residents, with the only bathroom off limits to the guests, unless it had been let as a bedroom.