@JustJane - had a good discussion today, and will do more over the weekend.
Wifey basically recognises im not exactly happy or settled in my current role. Concerns around additional commute time and increasing commute cost, and no bonus potential. Though she does say decision is mines, she is not unhappy or against it.
@omega13 - It would be an equally responsible role as I have just now, but without being "more responsible" (as in its not a "managers" job). As for FIRE; the base wage is higher, so more money will go into my workplace pension as pensionable pay is increased (resulting an extra £20 per month / £250 per year - so no big bones). But overall no impact on FIRE date in short term. As there is no bonuses, i believe the pay increases are more substantial (but not by much, though compounding over time it may be worthwhile). I worked out my last 2 bonuses were around 2% - hardly anything to shout about.
It is a more specialist role, but it is "within the business" so a bit more scope to move about. Less exposure to workplace politics (i think).