Congratulations Mum2toby!
My costcutting tips from my own wedding experience are: contact your local council's parks department - they will almost defintiely have a "floral" section who are much more reasonable than a florists. Glasgow parks department did my bouquet, the bridesmaid's bouquet, flowers for the tables (like Frieda, we had big fat church candles surrounded by flowers - bought the candles myself at the House of Fraser sale, which meant I didn't need candles for years!), flower arrangements for the church and matching hanging baskets to hang in the marquee for a fraction of the price a florist would have charged. They even did the corsages and buttonholes.
We also had a marquee wedding (Mum and dad are fortunate in having an enormous garden - albeit shared with others in the house, which has been converted into flats), so it was easier for us to be in control and choose what we wanted to spend money on. For us wine was important (hence the marquee and self catering, as we objected to paying corkage or through the nose for a mediocre hotel wine). We negotitated a discount with our friendly Oddbins, plus got the wine on Sale or Return. If you do have control over the wine, the Segura Cava is a really good, drinkeable bubbly, and is over half the price of a comparable champagne.
I laid out and printed out my own order of Service and gave it to a local printer to duplicate. I printed off the menus myself at home on nice paper.
We also used a friend's car to get to the church - it was only a mile and a half away, so I begrudged the hire costs! We put a ribbon on the friend's car - and at the church the ribbon was transferred to dh's silver Puma, in which the two of us drove back to the house. It was actually nice to have those few minutes to ourselves.
I bought loads of tartan ribbon and used that to tie up the menus - so they also became part of the table decorations.
The following year my brother got married and used the same format - the marquee at my parents. They saved money by getting flowers from the fruit market and then arranging them - but I know that that did frazzle my Mum a bit! She also made tonnes of tablet for the favours (I hadn't bothered with favours).
My Mum also made my and my SIL's wedding dresses, plus made the wedding cakes (got someone else to decorate them). But she is a bit of a super woman!
Like you, I wanted a classy, but not too formal wedding. The nice thing about the marquee was that we were in control. The day morphed from the wedding itself into a garden party (the weather was absolutely glorious - a beautiful may day), with people wandering down to the loch, before sitting down to a meal (provided by a local caterer, although the next year, my brother had a BBQ!), short speeches (with both my monther and I insisting on having our own say) and finishing with a ceilidh into the wee small hours.
We didn't have a top table - too formal for me - all the tables were round with ours, on which were sat dh and me, the bridesmaid/matron of honour and her dh, bestman and his dw and a friend acting as MC and his dp, in the middle, so it was easy for us to go and chat with everyone.
We also bought (cheap via the internet) single use cameras to put on each table to get different "pictures" of the wedding. We got some wierd and wonderful snaps!