We use Audatex estimating with direct links to your your insurance companies claims department.
Many insurer's employ steerage techniques to stop you using your own repairer. One of these is to try and apply an additional excess should you wish to use your own repairer.
I believe this to be an unfair term and condition in a contract, this is covered under a parlimentary act, and is covered under the Financial Conduct Authority Guidelines.
Should your insurer try to apply, bring their attention to these.
Unfair Terms5. (1) A contractual term which has not been individually negotiated shall be regarded as unfair if, contrary to the requirement of good faith, it causes a significant imbalance in the parties' rights and obligations arising under the contract, to the detriment of the consumer.
(2) A term shall always be regarded as not having been individually negotiated where it has been drafted in advance and the consumer has therefore not been able to influence the substance of the term.
(3) Notwithstanding that a specific term or certain aspects of it in a contract has been individually negotiated, these Regulations shall apply to the rest of a contract if an overall assessment of it indicates that it is a pre-formulated standard contract.
(4) It shall be for any seller or supplier who claims that a term was individually negotiated to show that it was.
(5) Schedule 2 to these Regulations contains an indicative and non-exhaustive list of the terms which may be regarded as unfair.
They should then waive the additional excess.