networkn:
Is it an option to have a conversation with said potential employer and let them know of the gap between the two positions, and that you'd like them to try and close the gap somewhat at least, and have them make clear what would be required from you, to finish the gap closing, that way you will know where you stand.
Yup - had that conversation yesterday, clearly outlining the gap.
It's the old "golden handcuffs" situation - my current job pays well, but also offers great benefits, with fully paid medical and subsidies for this and that and the other.
BUT - having thought about it overnight and the new potential employer raising the salary by a touch (as much as they could get sign-off for), I have decided I'll go for it. Mental health is more valuable to me than the financial aspects.