French visa confusion

Upvote:2

You can:

Apply for a visa in the UK once you live there (i.e. have some sort of long-stay visa or permit, not merely a visitor visa). That's the regular procedure for foreign residents in the UK who need a visa to visit the Schengen area and is not a problem at all. Since you said that you are “moving” to the UK, I assume you will have some sort of resident status there and this would seem to be the easiest solution for you.
Ask a French consulate in the UK to consider your application even if you don't live there. The difference is that you have to explain why they should and they might refuse but that's not impossible, see e.g. Can I apply for Schengen visa from London as foreigner? and Can we apply for a Schengen tourist visa while visiting another country on a short-stay visa?
Apply to renew your multiple-entry visa up to six months before it expires (article 9 of the Schengen Visa code). Rules for single-entry visas are more restrictive and having used your 90 days could in this case lead to a refusal but in your situation, with a multiple-entry visa and a legitimate reason for repeated visits, applying now in South Africa should be OK. There is not much time left for this, though.

Relaxed 102681

Source: stackoverflow.com