currency swap

I only have the BPP Revision Kit (not Kaplan) and so I can only help you on Keshi (which was a past exam question).
Unless Kaplan have changed the question in their Exam Kit, then Keshi was an interest rate swap – not a currency swap.
There are several ways you could approach the question (all with the same final outcome) and this may be of help to you:

Without the swap, if borrowing fixed then Keshi would have paid 5.5%
There is a benefit by swapping of 0.8%, of which Keshi gets 70% which is 0.56% less charge of 0.10% = 0.46%

Therefore Keshi must end up paying 5.5% – 0.46% = 5.04%.

But because of swapping, Keshi borrows floating and pays L + 0.4%

To make things ‘work’ the counterparty will pay L to Keshi. So now Keshi is paying L + 0.4% – L = 0.4%

Keshi has to end up paying a total of 5.04% (as above) of which 0.1% is charges – the remainder is 4.94%

So, to make things ‘work’ completely, Keshi must pay the counterparty 4.94% – 0.4% = 4.54%

Had it been a currency swap, then whether or not the principal (and the final repayment) need to be swapped would have to be told in the question – you would need to be told what the agreement was as regards to what was swapped, and at what exchange rates.