Theatre to Classical

I have only recently joined the forum but have spent quite a few hours searching the posts, but although finding a great deal of useful information I have not found a solution to the problem outlined below.

I have been playing theatre organs for many years using left and right-hand chords, pedals and occasionally filler notes from the bass clef.
Over the last ten years or so I have been drifting more and more towards Church music and now own a Roland classical organ.

I have responded to (but not committed as yet) to an opportunity to join a local group
of organists as a standby to help out on occasion. This is something I really want to do.

The problem is that my Mentor has said I would need to complete a piano course to become competent in reading the bass clef. Although this is a valid point the learning curve is very steep to obtain say a grade 3 or 4 in piano in a reasonable space of time. Writing in chords from the treble clef I find difficult as notation can vary even with an identical chord.

The question is (at last) Can I get by with chords temporarily whilst getting up to speed with the bass clef.

Thank you for reading and any help most appreciated.

Yes, if you are not accompanying a SATB choir at the same time.
That is to say, if you are just leading congregational singing (without choir) then you can busk your way through it, as you suggest.

(duplicate post deleted)

Thank you for your positive reply