Being FCA approved for corporate finance work in the UK

I have a question about working in IB/CF in London and being FCA approved.

I've been browsing job ads in IB/Corporate Finance and some of them list 'being FCA' approved as a requirement for these jobs. The FCA website does list corporate finance advice as one needing appropriate qualification: http://fshandbook.info/FS/html/handbook/TC/App/4/1 and unfortunately my ACA qualification doesn't quite cover that.

What I'm wondering is whether it is worth getting myself FCA approved beforehand (for which it seems I need to take the CISI certificate in corp fin exams: http://www.cisi.org/bookmark/generic...780&URL=ce…) or is this pointless effort?

I'm currently in audit at a Big Four, having nearly completed my ACA (and CFA L1) but moving to a transactions department soon. If my wish is to work in Corporate Finance, I'm wondering if this CISI exam is something I'll have to take at some point?