YABU
And so are they.
It's all about managing expectations. Weddings can be done on a budget and can certainly be done under £10k but these days it seems that the happy couple are not willing to compromise. Your ds could also be hinting about the expense in order to get you to cough up.
Here's how to do a wedding on a budget:
Get hitched midweek. Midweek prices are almost half the weekend prices and let's face it, if people wanted to attend the wedding they would take a day off work to do so. Those who would only go at the weekend are not worth having, thus saving you more money on guests! Go for a Thursday so that people can have a long weekend. Even a Friday is cheaper than the weekend.
Haggle. If you are booking a hotel/reception at an off-peak time then don't be afraid to haggle to get the price down even more. They'd rather have the booking than risk not having anything at all on that date.
Hire the photographer for the service only and encourage friends to take as many photos as possible.
Get your wedding bouquet from the supermarket. Just invest in some pretty ribbon and some extra dark foilage to decorate round the edges.
Make your own wedding stationery with embossed card, a colour printer, some ribbon and some sequins.
Make your own wedding favours by filling organza bags with sugared almonds as a traditional gift.
Ask the bridesmaids to contribute towards their own outfits. Many supermarkets such as Tesco have a range of bridesmaid outfits that can be worn again as party dresses.
Wedding cakes are expensive so get a cake stand and fill it up with lots of delicious little cupcakes.
A wedding buffet is cheaper than a sit-down meal.
Use helium balloons as table decorations.
It's more than possible to bring the cost of a wedding right down but of course it does require a little more effort and creative thinking. Your ds and his girlfriend may prefer to just cough up the money (or moan about it so you will) rather than have a budget wedding.