Hey Drowning Mummy,
Would think very carefully about trading leave for cash.... 5 years will seem like an eternity with no breaks and I'm sure your children would prefer having Mum around when they're off than sausages mixed in with those beans.... seriously, no leave will probably make you ill and your health is always more important than money...
If you agree a sensible budget with your IP you'll probably find it's not as bad as you're imagining...state clearly what you need to spend, ensure you have a contingency built in and allow an amount monthly towards the cost of birthdays, christmas and holidays - keep it realistic and your IP will support you, it's not in their or your creditors interests to make you have 5 years of suffering as the likely result would be IVA failure.
If you plan a realistic budget, then as Kallis says, you can choose to make additional economies where and when you can and set some asside for those unnexpected costs (they do arise - especially if you have a car!) In general you'll find a way that works for you, but you'll find it a lot easier if you don't sign up to an unrealistic starting budget....
Lots of threads and advice on here about hols....all good tips.... we stick with camping on small sites.... cheap as chips and if your lucky with the weather there's little to beat it.... Hotels in Barbados can be an incentive to think about for the end of the IVA though

)))
Best wishes
Martin