I may have misunderstood the question here, or I may not have been clear.So what were they using for the afternoon service between the restarting of services and the 6th of May?
WCRC have always required two rakes (and locos) to provide both daily Jacobite services.
Currently only the morning service is running - and that is as planned for this time of year.
My other comment was that in years gone by the "afternoon" service was even later, but still required a second train.
(Warning: speculative) An obvious potential solution would be to seek alternative timings to allow one train to run both services.