Would the Middle East be accepting of a South African teacher with a PGCE and 5 years of pre-PGCE teaching experience in Korea?

Speaking to the Middle East as a whole, yes, I think it's likely you could find a position there. The UAE specifically requires that your BA degree matches the subject you teach. IE; an English degree for an English teacher - regardless of the PGCE.

I don't believe that the Middle East would be accepting of a South African's teaching experience prior to obtaining the PGCE qualification in Korea or experience from any other country for that matter. Most requirements are 2 years experience post PGCE and have increased that to 3 years. I had more than 5 years of experience from South Africa prior to completing my PGCE which was not taken into account.

The Bachelors major should also be in the subject you plan to teach otherwise the PGCE doesn't not make any difference.

Brunei, on the other hand is extremely particular that experience has to be 3 years post PGCE graduation.