How do you replace microwave in a fitted kitchen?

[KathyDCLXVI]

Does anyone have experience of replacing an appliance like a microwave in a fitted kitchen and have any idea of how difficult it is? Our microwave has recently stopped working and we could call out an engineer but frankly last time dh did this it cost £50 call-out and it seems it might be worth replacing it.... only.... how would we find one that fits?! Or are they all much the same size? Can we get an edging to stick round the front? Anyone have any ideas?

TIA!

bump

You can just get a similar model to fit the space. If it leaves gaps, could you gett a new door to match your kitchen so it's inside a cupboard?

Cupboard doors are a sort of 80s yellowish pine, so I'm not sure we could get one to match; there's a sort of white plastic surround which makes up the size (as the microwave is smaller than the cupboard above it IYSWIM).

I assume it would be fairly easy to get one that's roughly the same size but I don't know if it would fit exactly, or if we can buy another plastic surround for the new model if it's slightly different (if that makes sense).