As others have said, the act of submitting the Planning Application (Forms and Plans can be quickly e-mailed to the Planners) takes about 5 minutes.
Preparing the Plans and forms ready for submission takes about 30 minutes.
Preparing the scheme (plans, reports, etc.) for submission can take many hours.
We are well used to clients who, starting off with big proposals, suddenly find that the cost of realising their dreams far outstrips their budget. Unfortunately, that also means that we are similarly acquainted with clients who wish to find reasons not to pay for the services they have received.
I imagine you received the design drawings before you decided you couldn't afford the cost of the scheme (it is unlikely that you would have pulled the plug after seeing the Existing drawings, only)?
As it stands I would offer to pay your Architect 'something' towards (B) because they stand a pretty good chance of securing a claim against you in the Small Claims Court.