My Jack Russell who is 18months old 3 months ago she had peritonitis and had to have an operation to remove a bad spline etc. Luckily she survived - but since this op she's been peeing around the house a lot, even though I take her out quite a lot. I take her out before bed at around 10pm and she sleeps in the kitchen, I've got up around 1am for a drink and there's a puddle on the floor - it's always very bight orange and there's always a lot of it.

Any advice would be gratefully received before I tear my hair out!

Bright orange pee doesn't sound right at all. I would advise you to get a sample of her pee and take her along to the vet for a check up asap. She could have an infection - this would also make her pee more often.