To me “you’d save £27.63 more” is a relative statement
Whilst the poster’s wording was ambiguous, the ambiguity was resolved in my mind by coming to the same result, hence my conclusion that was the most accurate calculation before hofnar threw the business days and interest received spanners into the works. The former being the more important in terms of magnitude. Even then he has been too simplistic because you need to tax effect the interest received.
It is quite clear to me that this question should not be resolved on a forum, but with the benefit of professional advice, whilst the cost of this would completely negate the potential benefits, being correct is more important than money.
Alternatively, if he has any common sense he will just pay the fee and save himself the time and effort and also, once the inability to transfer at the weekend is taken into account, a bit of cash.