No, l dont think you see the issue - it is not their borrowing...

No, l dont think you see the issue - it is not their borrowing cost; the market will want a higher yield since competing bonds will be more attractive.
RAT has locked income and interest, but relatively attractiveness of income will fall in time, that is why yield is so high. market price has it all factored in, no bargain currently, but l bought some anyway.
watch the 90 day bank bills - up to 6.62% indicating another rate rise soon. if it hits 6.7% then v likely.