I think it all depends on your own preferences of what you want, and where you live/want to get married. We had over 100 guests for a sit down meal so needed a large venue. Catering alone (3 course meal plus tea/coffee and finger buffet in the evening) was £80 per head, but it was important to us to have everyone we wanted there. Round where we live, that was quite cheap!! We also wanted a Saturday wedding as lots of people were having to travel, and we knew if we did it mid-week it would make it difficult for them to have time off work.
After that, we saved on a lot of things; I made all the favours, we bought the cake from M&S, I made decorations for the venue, we used an iPod playlist for music during the meal, bought my dress through a sale event, bridesmaid dresses from debenhams in the sale etc.. But overall the cost was still almost £24k. Church was £600, we spent almost £2k on flowers, cars another £500 etc etc.. Sure there were things we didn't 'need' - we had a live magician to entertain the guests as they arrived at the venue and pictures were being taken, and a 7-piece live band for the evening, we hired garden games like giant Jenga and chess for the daytime to keep the kids/drunk people amused.. The whole day was like our own little festival and we had the most amazing time, and so did our guests!
We live in Buckinghamshire, and it's expensive, my sister-in-law-to-be is getting married next week on a Wednesday in a country house near Leeds, and is only having 25 guests, her wedding is less than £7k.
Our wedding was expensive, and I did have complete moments of panic when I thought we were going completely over the top, and was ridiculous to spend that much money, but it was what we wanted. We planned it over two years, and paid for bits as and when we could, so spreading the cost. But I wouldn't change a thing!!