£40K a yr is unimaginable luxury to us! We have 1 DS, and live on 25K. No tax credits, but £5K of that is my disability benefits. We rent a 3-bed house, and used to have Freeview, but just got a good bundle deal with Virgin Media that costs the same as old landline and internet (I need a landline due to hearing problems).
Things like rent, bills and cars might not have much wriggle room for saving cash, although you could go for a smaller home. However, virtually everything else on your list could either be cut down massively or got rid of altogether.
Food: unless you vastly overeat and only buynluxuries, etc., no way do you need to spend £600 a month.
Hair: £60 is top city salon prices. Find a good local hairdresser and have your hair cut less often (maybe change style?). I don't know anyone who has their hair cut once a month, even friends who are very well-off. No-one needs to get their hair coloured, but if you really don't want to forego it, then have it done more cheaply, or buy a DIY at home kit. I use a £5.99 one from Boots and it's as good as when I got it done in a salon.
Tv: get freeview or look for cheap packages including line rental, broadband, etc.
Presents: this is the daftest bit of your list. People just don't spend that kind of cash on gifts, and surely not monthly. Just slash this section almost completely. It's bizarre budgeting for several hundred pounds a month to spend on gifts, unless you're Elton John! People can have a box of chocs or a book you got cheap, kidscan have something you snap up when there's a flash sale on at ELC or similar.
Also, if money is tight, you put your own family first. Others expecting big pressies can go whistle for them.
If you look for good offers, you can save money in every area. Sign up for emails from companies and receive lots of money off vouchers and offers online. Go to price comaprison websites for everything. And above all, stop seeing monthly expensive haircuts and swanky pressies for others as necessisties!