If the house meets your current needs, then you should probably stay there.
You have a comfortable mortgage.
You have cash in the bank
If you have a cheap tracker, then this would also support staying where you are as your housing costs are artificially low.
If you don't have a cheap tracker, you should look at using your cash savings to reduce the mortgage. This is the safest place for your savings.
If you have to move at some stage, then you should sell your house first. If you can't get a mortgage after you sell , then you can rent. Perhaps not ideal, but not bad either. It's probably better to rent a house you like than to own a house you don't like.
Brendan