To be mortgage free

We are on the way of overpaying our mortgage regularly. I have set up a standing order for £100 a month. It is on the top of our £862.42 payment.
Just £100 a month should shorten our mortgage term by 3 years and save us over £10000 on interest.
We really should make much more than just £100 but by some magic we always spend it.

 

Our monthly account is:
£2000 goes into joint account. (£1000 from me and £1000 from my husband)
£862.42 mortgage
£140 council tax
£26 virgin broadband + line (prepayed)
£46 home insurance (payed yearly - this is part for 1 month
£320 food bill (approximately)
£25 water bill
£91 electricity & gas!!! Having tumble dryer is expensive!
£165 child minder 
£100 reserve( for presents, VET, minor repairs, boiler service, restaurant, baby stuff)
We should save around £224.58 a month

Unfortunately this £200 just vanishes from our account. So i have decided that we have to be more ruthless and stop spending it!
I set up standing order for £100 just to be sure that overpayment will be regular. My goal is to cut on food bill and other spending (take the electricity down) and make £300 overpayment a month.
So far for January I have made it. Luckily there was some left over money on our joint account.