This - as written - is complete rubbish. Your wording would mean a UK bank can't lend to a UK GBP earner on property in the UK.

Anyway, I certainly know plenty of CHF earners with mortgages on property in Austria, although all with Austrian or (in one case) German banks. Borrowing from a Swiss bank is not impossible but difficult as they are generally unwilling to lend if the security is a foreign asset. Depends on who you are and the bank.