I'm in the same boat with this fund, I've slightly lowered my contributions to this one but will ride it out for a few more years.
As an FYI I work with one of our companies funds teams quite closely and have had some interesting conversations on fund growth within the SA market. One point they emphasized was that statistically, and for a number of logical reasons, you will have the smaller up and coming funds outperforming the larger ones as they grow their AUM over time. So you take a fund house like Coronation which is very established in the market both in presence and in terms of the sizes of their funds but rather than dump all your cash into say the Top20 diversify within a smaller fund house but that is also a similar mandate.
Also be aware of who the actual fund manager is, their track record as well as if your favorite fund is changing hands to a new manager. If an option I would rather invest in a particular person in the industry versus a particular fund or company. Obviously depending on if they are still managing similar products.
I haven't any affiliation with the company but Anchor Capital has had incredible performance in their high equity fund. Small fund house, good management team, diversifying into that fund has at least mitigated the lack of performance in the Coronation fund.
Or stuff it, just buy shares in Anchor and double your money every six months