Upgrade idea

Hi guys,
Trying to see if an upgrade is workable. I do some photo editing from time to time, so just looking for a Core i7 / IPS laptop with decent power consumption. I don't really need the dedicated graphics / often.I use an trusty Precision M4600 (PremierColor RGB LED IPS, Core i7 2760QM, Quadro, 500GB HDD).

This IPS screen is stunning once calibrated. It's hugely functional. Problem is the RGB LED version was implemented to only runs on the dedicated graphics card, so the laptop runs hotter than the standard M4600s. Being almost always plugged in (180W charger) is not great for electricity usage. This is the main reason for wanting to upgrade.

Dell quickly stopped using IPS after M4700 for a long while, so I'm not sure I'll find something great value given that only limited models with IPS were made - I wanted to look anyway. Though I do understand that sometimes replacement is not always economical (there is truth to the "don't fix what's not broken" saying). Whilst using more electricity isn't ideal - getting a replacement will cost more certainly. (assuming 180W always on - that's £180 per year in the UK? certainly in reality it will be less than 180W, still).

Have looked at XPS 15 though as it's a work machine, the thought of dropping that beauty is a bit frightening (also slightly weary of the new 4k resolution/windows scaling - returned a M3800 4k version this week due to CPU coil whine). Would be grateful is someone could suggest something from Dell that I should look at. If Dell options don't pan out, might just do an SSD upgrade / swap for a ZBook 15 with IPS / or save towards a DreamColor modes.

Thanks