I bought a 2.5 Tdi Elegance a couple of months ago with about 25K on the clock.

It's had one service and is on the variable schedule. I've no idea when the next service may be due.

Do the electronics alert you to ' Service due in 1500 miles' like a Merc/Audi, or what?

Any help greatly appreciated.

I think it gives you 1000 miles warning. Think you should get anywhere between 9000 and 30,000 miles between services depending on how the car is driven.