I'm not sure what figure you're referring to - I.e where you're seeing 1.13%. In had a quick look back through the thread and didn't catch it. But the CRR is not your answer
The essential is that notionally the bank borrows money from the interbank market to lend to you. Say for 5 years. So the prevailing 5 year rate on that day is A. If after 2 years you want to break then the bank has to place your money back on the market - this time at the prevailing 3 year rate so that there is no maturity mismatch. The 3 year rate is B. The difference between the two is the basis of your break fee, unless B is higher than A. Yield curve shenanigans can mean that short term rates are higher if the market is pricing in particularly unusual activity, but typically the shorter term is cheaper - resulting in a fee being payable. A flat curve works for us consumers.
This has been the case since the mortgage credit directive came into force. That would override any contractual terms that predate the mcd.
They also have a break fee calculation example and use the phrase "cost of funds" rate from 2014 & 2015 in their example. This rate does not correlate to the published Cost of Funds rate, so I suspect that there are different cost of funds rate for different lending types.