Compare written scope, included participants, deliverables and exclusions alongside price. Keep those fees separate from the government gift and official processing charges.
Ask what a quote buys
Determine whether the quote covers an initial opinion, evidence preparation, filing, requests for further information or later immigration steps. A low consultation fee and a full representation fee describe different work. Do not interpret either as payment for a favourable decision or an assurance that government charges will be refunded.
Compare what each quote actually buys rather than the figures, since the same headline can describe very different engagements. Ask each adviser for the scope in writing: what is included, what is expressly excluded, whether the fee is fixed or an estimate, what would cause it to increase, whether it covers responding to questions later, and what happens if the matter does not proceed. Establish whether amounts payable elsewhere are included in the quoted figure or additional to it, and confirm those independently from official materials.
Where several advisers are involved, ask each whether any part of their scope overlaps with another's, since paying twice for the same review is a common outcome of engaging professionals separately without anyone comparing the terms. Ask finally whether any adviser would be paid differently depending on which route is chosen, since that is a question about incentives rather than about price and it rarely appears in a quotation.