Thank you for making an appearance here Damian. Your father was quite a character in the best possible way.
Always tough even when the passed had a long life, a dreadful loss.
As many of the bikes and frame sets he collected were of a reasonable size range, there will be demand of course.
Metering out the presentation will still probably be best if there is space to store.
from his Flickr account there are many frame sets at hand. Greatest demand may be outside the UK.
He had a good eye for quality builds.
Things are no doubt different in the UK, but lining up a source for boxes suitable to ship a frame with the fork removed and packed I suggest be one of the tasks.
‘His Flickr account can provide good reference as to areas to focus images of the frames.

Some have used Flickr as a means to present items to sell, placing a card in the camera view with notes and even an inventory number that the item can be tracked with could be of use.