As pointed out, those rates are targets only and each broker will be different. And that's a lot of legwork, prone to error.
Here's a faster / better solution:
Go to
http://fxtrade.oanda.com/fxtrade/interest_calculation.shtml#
In the 2nd paragraph, click on the hyperlink "FXTrade's Interest Rate Form".
A new browser tab / window will open. Choose your currency (-ies) from the 20 offered. In your case, select both GBP and CHF, by holding down the CTRL key. Enter your date range, going back to early 2001 for the major currencies, later for others.
Now click on "submit". Save the results as a "text file", rather than HTML. Voila! Now you can easily read that into Excel or another app. It'll only have entries on those dates when the rate changed, up to a few dozen times at most. Clean up those extra 0 entries at the beginning, if any.
Bid = borrowing rate = credit when you are long a currency.
Ask = lending rate = debit when you are short a currency.
You'll find some very detailed calculation examples there. Most other dealers compute interest debit / credit once a day, rather than on a second-by-second basis, and, of course, may have slightly different rates, but the basic concepts and math remain exactly the same. Enjoy.
