Steven,
Your source re demolition is correct.
Alder House was a large double fronted stone built building standing in it's own grounds behind the stone wall, parts of which remain. The entrance to the grounds was Alder Grove...there is one stone pillar remaining to be seen on google. The wall continued along Galloway Lane and around into Waterloo Road...the wooden door in the wall, still present, was a pedestrian side entrance, and shows the original height of the wall. Inside the grounds which were as I recall park like, was a further house, which I believe is still present. This second house was occupied by one set of the parents of either Mr or Mrs Jones, who were resident in Alder House. This would be around the early 1960's, as I remember being invited to the house for their daughters birthday party. The grounds were extensive and they kept their own chickens. Alder House was built at right angles to Waterloo Road so the main front looked along a sight line parallel to Waterloo Road. I also recall there being a terrace across the front. Beyond the boundary of the garden (Waterloo Road) there were two or three fields, which were originally,( so it was said) kept free for a possible link road, which would have run to Dawsons Corner as part of the Dishforth link. Those fields were subsequently infilled with three detached houses at the Ingrow Terrace end, and then joined by more to fill the remaining gap.
As for a photograph, maybe the Pudsey News Archives could help?
Regards