Hi Chrissi
Amaryllis, West St. Berwick upon Tweed
The Maltings Cafe, Eastern Lane Berwick upon Tweed
both of these do meals on Fri and Sat evenings, good for coffee & lunch.
Queens Head Hotel, Sandgate Berwick upon Tweed lunch and dinner
Oblo at Harbour Rd Eyemouth - Bistro
Wheatsheaf Hotel at Swinton - dinner
Fisherman's Arms at Birgham between Coldstream and Kelso lunch and dinner
The Tree House at Alnwick Garden - 28 miles S of Berwick
just off A1 lunch, afternoon tea, dinner on fri and sat might do early evening meals on other days.
Hope thats of some help.
There's also Cafe Curio Bridge St. Berwick which I've heard good reports off but haven't tried.
Are you going to be in Northumberland/Borders on holiday?