Turns out I didn’t need to ask anyway. Logged into my acount one day and had 2 options – ‘Apply’ for a new car (Essentially just prefilling a load of paperwork). Second was ‘Extend lease’, despite asking MB twice, being told no both times, I clicked extend, got a small page with some info telling me I can still order a new car with no hassle in the mean time, MOT, Insurance etc stays the same, followed by a tick box confirming I was ok with this, then a page to confirm my new lease end date in 2026!