Could be wrong, but I think a.k.a brands paid about $300 for a...

Could be wrong, but I think a.k.a brands paid about $300 for a half share in Culture Kings. Summit Partners, who own a. k. a., have also just bought the remainder (40%) of Quay Australia, purveyors of sunglasses and accessories.
If they really want to swallow and digest (the hard part) any more Aussie rag trade businesses, then they would need to offer at least another A$600m for controlling interest in City Chic, given that the market cap is already almost $1000m.
The current owners probably wouldn't think - correctly or otherwise - that they needed outside assistance in the form of a buy-out to achieve that sort of return.