Where are you based?
Our caterer is based just outside of Bristol, and is doing sharing platters for us. We're having just starters and mains, as we are going to look at having an ice cream van for dessert. For 100 guests, it's come in at under £3k, and the menu was the only one that we both (my fiance is vegan) looked at and went 'yum!'. He's also using all local produce.
The company is called The Full Spoon.
Whatever area you're in, my advice is just to keep asking around. Try going to wedding fairs too, as you'll often get discounts if you book through a wedding fair.
Good luck! X