You are free to consider any clinic you like, on the marketplace or not. The practical difference is not about quality, it is about what applies: GetClinic's booking and refund rules reach a deposit paid through the approved route shown at checkout, and they do not reach a payment made outside it.
GetClinic lists the clinics that are on the marketplace, and makes no statement at all about clinics it does not list.
Not listed does not mean not good
A clinic being absent from GetClinic tells you nothing about it. Clinics are not on the marketplace for all sorts of ordinary commercial reasons.
GetClinic's verification is an administrative process about documents rather than a judgement about the standard of care, so its absence is not a judgement about the standard of care either. What it does and does not establish is at how we check clinics. See also what "verified" means on a clinic profile.
Why the payment route matters
The Refund & Cancellation Policy attaches to a clinic booking deposit paid through an approved refundable collection route. That route is identified at checkout, along with who is being paid and what effect the payment has.
If a deposit never travelled by that route, there is no deposit for those rules to act on. GetClinic cannot return money it never received and never processed, and the refund schedule you may have read about does not apply to a payment it had no part in.
Paying a deposit off-platform is not permitted
Direct off-platform payment is not a permitted route for a GetClinic clinic booking deposit. If a clinic asks you to send a deposit outside the route shown at checkout, do not pay it, and contact GetClinic first.
That includes a bank transfer to an account sent to you by message, a request to pay through a different website, and any last-minute change to payment instructions. Read paying safely, and spotting fraudulent payment instructions before you act on any instruction of that kind.
The treatment balance is a different question
The balance of your treatment price is not the same thing as the deposit, and it may lawfully be paid directly to the clinic where that is disclosed to you in advance.
If you are paying a balance directly, verify the clinic's legal identity and the account holder before sending anything, and treat an unexpected change of bank details as a warning sign. See when you pay, and who you pay.
What GetClinic does not promise about price
GetClinic does not promise that a clinic will hold a price, and does not match or beat prices.
There is no price guarantee here, in either direction. The clinic sets its treatment price, states its own inclusions in its own written offer, and can change what it charges within the disclosure rules in the Booking & Deposit Terms. A change to price or scope has to be disclosed and accepted before it binds you, which is explained in changing or rescheduling your booking.
So do not choose between an on-marketplace clinic and an off-marketplace one on the basis of a price promise from GetClinic. There is not one to weigh.
If you go elsewhere
Nothing stops you, and you are not doing anything wrong. Just be clear about what you are giving up: the disclosures required at GetClinic checkout, the refund floor in the Refund & Cancellation Policy, and a booking record held by a third party.
If a clinic on the marketplace suggested you book with it directly instead, that is worth telling GetClinic about. See how to make a complaint.
GetClinic is a technology marketplace. The clinic you choose provides your healthcare and is responsible for it. This is general information about how GetClinic works, not medical advice. Only the clinic's qualified healthcare professionals can decide what treatment is right for you.