OP - You'll get used to the way some people talk on here - just ignore them :) Some people don't have anything better to do with their time!
Firstly, it's fantastic that you want to try for a baby! Remember it's not 100 % about the money, it's also about the emotional support you can offer them along side that.
Also, I apologise for this long message! >.< Basically, what I am trying to say is that you cannot change you spending habbits drastically overnight. It takes practice, trial and error! Have a Google of "You need a budget - YNAB" - I haven't used it yet, but it's supposed to be AMAZING.
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Try and look at each expense, one expense at a time. It's a little less of a shock to the system then.
So firstly, maybe decrease your food budget by say £50 a month. Put that £50 straight into a jar labelled BABY! The more the jar adds up, the more you will want to cut back to save for the baby jar.
As a side note/comparison... We are two adults (and a step child on weekends), our grocery bill (including cleaning products etc.) is budgeted at £200 a month absolute max. We never spend this much, in fact usually a lot less because we prepare meals from scratch, or near-scratch, look out for offers and freeze everything most things! We shop in Tesco, Asda, Sainsburys, Lidl (occasionally) and Waitrose (occasionally)
We also have two cats - 1 kitten and one adult. The kitten has 2 Felix pouches a day, the adult has 1 and they have dry food throughout the day. They used to be a posh brand of biscuits which we weaned them off of on to Go-Cat! Which is a 1/3 of the price and still not supermarket basic brand!
We currently spend about £30 pm on wet food, £15 pm on dry about £25 on wood pellet cat litter - we will also be switching to a slightly cheaper store brand clumping litter gradually. After all, it is literally just being put in the bin. We use a lot of litter because they are purely indoor cats! So I understand how expensive they can be. Try and buy what is on offer - your cat's may appreciate the change of food?
Perhaps then try changing where you shop, when you feel a bit more confident. (Personally, I shop all over the place and don't do my shopping in one store.)
When you feel ready you can move on to the next expense!
If the Virgin phone / TV doesn't include internet, get rid of that! We have just standard free-view (contemplating buying a recording box to go with it for £120 ish). Our super-fast internet with BT is £35 pm, which includes a phone line (but we have no phone to plug into it! LOL).
We don't necessarily go without, we're just more careful!
Good luck! Keep us posted with how you get on :)