I had a broken exhaust mount a couple of years ago. Lexus quoted me a similar price to replace. In the end, I took it to a local welder who fixed out for me, £30 iirc, he didn't disconnect any of the batteries, should he have?
When I had the car in for MOT in January, whilst performing the health check, they noticed that part of the exhaust shield had come away. I had a mechanic mate fit a Catloc-likee in February, and he couldn't see anything wrong with the exhaust shield. If Lexus mention it next time it goes in, I'll go and see the welder again.
Edit: It seems it was 3 years ago, I just found my post, you commented at the time stormchaser.