The bank are within their rights to make the loan offer conditional on taking out PP, so no comebacks there I think (i.e. if you don't like the conditions, don't take the loan-nobody is forcing you to do anything). However, they cannot insist that you take out their PP product.
On the overcharging issue-I would contact the bank and ask them to explain in more detail how they calculated the fees and charges.
Note-you don't actually receive the €4,826-this would have been transferred directly to the PP underwriter, but you are still liable for interest on it-so I think you may have misunderstood this part of the issue.
Hope this helps.