Salary on promotion

[Greenbanana7]

I am an in house legal counsel with many years experience. I am going for a promotion to senior legal counsel with management responsibilities. Work haven't confirmed the new pay scale. Trying to work out what I should ask for. 10%, 20% or otherwise? Anyone got any experience or views? Thanks

If there is anybody else in this role I'd expect to be paid the same after a short period.

There isn't, it's a new role

Do you know the external market rate for that role?