Also a family of two adults and two kids with 5570 incoming a month. We don't thank god have anything like your debt burden but between mortgage and childcare, we are paying out almost 4000 a month, so not a huge amount of disposable income.
A couple of things that strike me
Gas 140 pm - this seems very high as a annual average. Can you change supplier? Or look at your heating controls again - is it timer or temperature controlled? We just got a new heating control system (subsidised by a SEIA grant) and it is making a big difference to the amount and how we use the heating
Electricity 70 pm - seems reasonable but you can reduce it by up to 14% by changing to Bord Gas, paying by direct debit and being an existing customer
Gym 45 pm - cancel it straight away. Lots of ways to exercise outdoors or indeed in front of a DVD if its raining
Get rid of prize bonds
UPC 130pm - we have a TV, broadband and phone package (which includes free calls at certain times) for 70. Switch packages immediately.
Life assurance 110 - you should be able to get a better deal on this. My outstanding mortgage is not hugely smaller than yours and our life insurance costs 33pm. Bare bones - mortgage paid if we die, nothing for illness et al.
Saving say 10% on energy costs, cutting gym and prize bonds, changing UPC package and halving life insurance saves you nearly 200 a month. Add another 50 for a change in phone package and you are beginning to have an emergency fund for doctors bills, Christmas presents, clothes etc
What about childcare? 1675 is a lot for 2 children - are they both pre-schoolers? Depending on where you are, there may be cheaper options. If in a creche, can you negotiate a discount? Or look into a childminder (in their own home)? Although if the kids are happy where they are, I can understand you would be loathe to make a change unless absolutely necessary.
Could you cycle to work? Only use mobiles in an emergency - texts for all routine communication and landline or Skype for chats.
Check out the money matters thread on rollercoaster.ie - a more frugal set of people I have never come across! Fantastic money saving tips on everything from grocery shopping to energy use to psychological tricks to stop you spending money (my favourite being freezing your credit card in a big block of ice - defrostable in emergencies but you'd think twice about doing it for an on-line impulse buy!)
Also for winter clothes for the kids, check out jumbletown.ie - lots of people giving away clothes and toys in good condition for free
HTH