Landline and Broadband with Vodafone - cancel for a month?
You need to give a month's notice, you may be within a contract, and you will have to pay a fee to reconnect. Then on reconnecting you have to pay a month line rental upfront, and may incur higher fees until your "bundle" takes effect.
Mobiles with Vodafone and O2
Nope. You may be within a contract, but either way the mobile phone company's require a month's notice to disconnect. And, as above, the higher initial bill from paying a month's line rental upfront. You could go down to a lower tariff, but that takes affect from your next billing date - then when you change back you'll be waiting around til the next billing date to get all your minutes back.
Electricity with Airtricity - could we disconnect for 1 month? but would ther be a re-connection fee? I think it's around €100
Car tax - not a runner paid up
Car Insurance - stall policy? There's usually a fee of about €60 to make alterations to your policy. So you could cancel your policy and get a refund for the rest of the year, less €60, and when you start a new policy your premium might be higher.
You're going away for 4 weeks... not only will you be causing yourself a lot of hassle cancelling all your bills, then you have even more hassle and expenses of setting everything up again! It's a crazy idea!!