These forms, and most importantly the notes, vary a great deal in quality. Ask around the solicitors in your area, explain what is needed, and get a quote is my advice. Don't use a will-writing service. My late father used a bought form and the will was rejected for probate which caused a deal of trouble though we did manage to resolve the difficulty by finding a witness and having an affidavit sworn; in other circumstances the witnesses might not have been traceable.
What does the estate consist of? Are there any children,including adult ones? Do they have children? What happens if one child predeceases the testator? These, and many other questions, are what a solicitor will ask, all are important and not all will necessarily be covered by a will form and its notes. Considering what the solicitor will charge, against the value of even quite a small estate, the 'cheap way' may prove very expensive. And, above all, the solicitor is covered by insurance and by the professional governing body. You have nobody to complain about and get redress from if you do it yourself. No sensible lawyer writes his own will; there is a reason for that!