I didnt use a specific weaning book... I just swapped things in recipes.
Eg if a recipe needed milk, I used her formula (nutramigen).
For butter, I used Pure a dairy free spread available in most supermarkets
For yoghurts I used alpro soya ones.
I started off with fruit/veg purees mixed with formula. Maybe added some Pure butter to mash potato & blend in chicken, corned beef etc... Baby rice/porridge etc just add nutramigen. Toast, bread sticks etc fine for finger foods, ella's kitchen pouches most are dairy free, organix crisps again check label but most are fine, ellas's kitchen ginger & apple baby cookies are great too for chewing/teething.
As she got older I found most breaded fish fingers were lactose free (batters not!). Custard you can make yourself using birds custard powder with the formula, even add som cocoa powder to make it chocolatey for a treat
Tesco have a good 'free from' aisle. We got choc buttons for her there, alpro soya desserts, breads/rolls etc (Though normal pan loaf is fine anyway).
Most foods are fine. Caitlin is growing out of her allergy atm and im slowly introducing dairy - she can now eat cheese, youghurts, pastry, pancakes, butter etc. I found that a dairy free diet is quite easy if you stick to simple foods - and very healthy. Eg meats, fish, veg, fruits, baked beans, pasta, tomato based sauces, spaghetti hoops etc. Im not a great cook so didnt really look at recipe books much. Caitlins food was all very simple lol! Or from a jar
(at least 60% of 1st stage jars are dairy free - you just have to check label every time you buy!)