we almost did it...
Registry office wedding: (~£100 with all the registration fees and petrol to get there etc).
Wedding dress (~£150)
(brides mum bought shoes as a present)
bouquet was made by wife.
Suit, shoes etc (~£100 from TK Max)
dinner in a pub where guests paid for themselves.
Decorations were all handmade, and plenty of cheap fairy lights etc. (call that ~£100.)
food at the reception was a buffet that we prepared before hand, and setup on the day. (~£150) (that's a vast amount of food!)
the venue for the reception was a town/village hall, that was £25 per hour. (4pm = 1am (£225)
a bar would have cost £250 to hire in the bar and staff, and we'd have then had to buy drinks. so we spent (rather too much) £600 on drinks, (including a cask of ale, lots of lager, cider, wine and spirits) and said to guests if they had special requirements then then should bring their own. (there was enough left over that we were able to give it to a friend to provide all the drinks for their wedding also. -so we could have spent less, also could have spent less buying cans rather than bottles, but thought everyone stood around drinking cans of beer didn't look as nice...
a bunch of musical friends put together a band and played for free. we used the bands PA system and mics to do speeches and to have a laptop with music.
we bought my ring from etsy, if costs about £10, for a carbide steel band, which whilst cheap, doesn't scratch easily (it's the same stuff they make saw blades out of). DW's ring came from a jeweller, and cost £100 but was paid for entirely with clubcard vouchers.
So with a lot (and I mean weeks) of making decorations, a couple of years planning, and buying things at the right time (like fairy lights for decorations after Christmas when they are on sale), plenty of browsing on ebay. and making a lot of stuff... our wedding cost £1800, given that the biggest portion of that was essentially just a free party for our friends. it should be reasonably simple to get everything coming in at less than £1.5 grand.
What I would say is, it was most of a year spent making at least some stuff, or planning, the best part of a week before hand spending all day cooking cakes, treats, and savoury items. On our wedding day we set-up the reception ourselves. and packed it away on the same night. because we couldn't afford the hall hire until the next night.
If I had to do it all again, I'd rather save the stress and pay someone to do it!