Liverpool has dozens of firms offering SEO, from large full-service agencies near the waterfront to one-person consultancies. Their websites tend to say the same things, so the useful comparison is about what they will do, not how they describe it.
Start with the scope. Ask for the list of jobs in the first three months and the number of pages, profile updates and links each month. A good company answers that in writing.
Then look at the terms. Twelve-month contracts and setup fees are common in the city, and both shift risk onto you. Rolling monthly plans keep the company honest.
Finally, ask how results are measured. Rankings alone can look good while the phone stays quiet. Calls, forms and bookings tell you whether the work is paying for itself.