Aye.. It's a tough tax bracket.
To clarify, this is called the "Β£100k tax trap"
The quoted 69.5% is only on the income between Β£100 and Β£125k. This is due to simultaneous reduction of personal tax allowance between those income figures.
Tax drops back down to 45% above Β£125k.
In England the tax trap is 60%.
A common way to avoid the tax trap is to put anything above 100k into your pension, tax free. Only when you earn above Β£130k it's worth suffering the tax trap.