Finally on laptop so can reply properly. I see that you're planning on Registry Office - which should keep things relatively cheap :) We're actually marrying in our local church but as we're regulars there anyway we have massively reduced fees.
What we've done so far is:
Church ceremony - minimal fees as churchgoers
Cars - Dad is driving me to the ceremony and DP's Dad is driving him. We still need to figure out how to get to reception, but I'm sure there'll be at least one person with space in their car.
Flowers - I'll be getting a supermarket bouquet but a friend got married in the Summer and just picked them so cost her nothing
Rings - Argos, £155 for the two - DP has a plain band and mind is slightly more decorative but still only £90
Dress I got brand new delivered off eBay for £70 (though my parents paid for it)
Shoes I managed to win on eBay for £11 - worn once but in excellent condition
Jewellery I'm borrowing off a neighbour
Hair and makeup I'm doing myself, but I'm keeping it fairly simple
DP's suit was from primark - £45 (trousers, waistcoat and jacket) and shirt/tie from Tesco for £18
Best man's suit is the same
Bridesmaid Dresses - £70 brand new off eBay for the 2 though you could just not have bridesmaids
After the ceremony we're have tea / coffee / cake in the church hall - hire is free but only £30 if you don't go to the church or you can look into cheap village halls. My sister hired a village hall and did the decorations herself and it looked fab. Cake we're buying from costco - I think it's something like £16 for a 45 portion cake! We have around 60 guests so will probably buy 2/3 as the 45 portions are quite small so will buy extra just in case. Can always take it to the evening do if there's much left over.
Then the evening do is in the local sports and social club for £265 including DJ. We're getting married at 4pm so tea / cake should be fine until evening buffet around 7pm. We're doing the catering ourselves - with a lot of help from family to make sandwiches etc. You could also look into local rugby clubs
We've decided to not bother with a hotel and just go home that night. Invitations we're making ourselves, has cost us about £20 for the materials. Photographer we're using someone my sister knows, it's costing us £400 for the ceremony and formal photos but I'm sure you could get it far cheaper if you asked local colleges / friends / even put out a shout on one of the wedding sites.
If you want to do drinks yourself check out deals in supermarkets and buy when they have offers on. Also Sainsburys do glass hire and you just pay for any breakages. BHS are also pretty good for bridesmaid dresses and i know my friend got the sandwich platters from M&S for pretty cheap, though I can't remember the exact cost.
Have fun planning the wedding :) It's very exciting!