Easily done.
Look in TK maxx or online for your bridesmaids dresses and your dress.If you buy online from abroad make sure you use someone that has really good reviews from people in the Uk and go to local bridal shops and try on dresses and get a clue of what style you like and what suits you,it makes it so much easier when your looking online for a dress.
That's how I got my dress and it was the same as the one I loved and had seen in a bridal shop here but cost me £1,000 less.
Dunelm mill sell really lovely artifical flowers that can be used as bouquets for you and your bridesmaids,you can add ribbon/diamante pins for a couple of extra pounds to make them look like you've bought them from a bridal shop.
If your using fresh flowers for your button holes,bouquets and table decorations check out the prices of local independent flower stalls compared to the local supermarkets.If your buying alot of fresh flowers an independent stall will usually do you a good deal and some can even make up button holes for you.
When I got married myself,my Mum and my Matron of honor made the bouquets for me and my Matron of honor and my bridesmaid,the buttonholes for everyone(they're really easy once you get the hang of them)and made all of the table decorations.
It only took us a couple of hours the night before to make all of the button holes and do all the table decorations(lovely fresh flowers in unsual jam jars for our vintage summer garden wedding)the bouquets were artificial flowers and we made those a couple of weeks before)and I made a fresh flower bouquet to throw.
We bought matching suits for my DH,my Dad,and our 2 oldest sons(they were my DH's best men)online,we also bought our youngest DS's suit online.
My DH designed and made our save the date cards,invitations and thankyou cards online.He's brilliant with anything like that so if you or your future DH or a family member or friend has a really good printer and is able to make them for you you can save a small fortune on invitations ect.
If you have the same people at your wedding throughout the day(so no seperate day and evening guests)then you could have the hog roast for one meal and then do a high tea(cakes,scones, savouries and sandwiches)for the other meal,you can order platters from Waitrose and M&S.Depending on when your getting married and your guests you may want to have the cooked meal in the evening.
With the wedding cake places like M&S,Waitrose and Patisserie Valerie are usually the cheapest and the cakes usually taste as good as they look.
That or if you have a friend or family member that would like to make the cake for you as a wedding present that could save you £200-£300 at least.