What's the very best dry food?

Dear Think Tank
I've just inherited Bonnie, a seven year collie, from an elderly relative who sadly passed away. Bonnie's been used to a dry complete food but a really basic economy brand probably full of E numbers and I'd really like to put her on something a lot better.
Where do I start? I've not had a dog for decades and I'm blown away by the vast array of foods I'd never even heard of before mentioned in your magazine! There's only a fraction of these more interesting sounding brands on the supermarket shelves.
What's the big differences - apart from price? I'd like to give Bonnie the best possible food. So which is it? And before anyone says raw, I can't stand the sight and smell of meat - we're a veggie household, so dry suits us all just fine!
Sally Millar, Esher, Surrey

Diet is the last thing I would be altering at this point. Bonnie was used to living with an elderly person, perhaps as a sole companion since she has now moved in with you. You say that you are a household, so that suggests at least two people, possibly children – all big changes. Give Bonnie a chance to settle in. This is going to be a big change for her so I would keep her diet to exactly as she is used to eating for the time being.
Change of environment, change of water, can upset the balance of the bacterial flora in the gut. The diet is the one feature which is easy to keep constant as it sounds as if you know what Bonnie has been eating. Once she has settled in, then you can think about changing diet and routine.
As a side thought, I would definitely be inclined to either plug in an Adaptil DAP diffuser and/or fit a DAP collar, to help Bonnie settle in.
For a vegetarian household, dried food is ideal as it is visually a long way removed from meat, and without a meaty odour. A seven-year-old collie is middle aged so an adult food will be fine. Has Bonnie been spayed? Is she at the correct bodyweight? Choice of food will depend on whether she needs to lose weight, or whether she is at the correct bodyweight but has a tendency to gain weight.
Then one should consider other features of Bonnie’s health. Does she have dental disease? Is she used to exercise? If she is a border collie, she will naturally love exercise, but may have had a low plane of exercise whilst living with an elderly person. She may therefore be unfit and will need a carefully rising plane of exercise. Indeed, do you know if Bonnie’s parents had their hips scored, and eyes tested? Does she have any other health issues, hidden or diagnosed, which might make a prescription diet more suitable?
Which brings me to a burning question – when was Bonnie last examined by a veterinary surgeon? If it was more than a year ago, then I would suggest a routine appointment when you can raise any other concerns as well as the ideal food to feed her.
Alison Logan, vet