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Prospective members are rigorously vetted before being allowed to join our national network of accredited installers. The implementation of a 12-point vetting procedure means that a number of glazing companies who apply to join DGCOS do not satisfy our accreditation requirements. DGCOS also carries out frequent audits and monitors level of customer satisfaction.


  • Undergo a five point credit and background history check on the proprietors/directors which includes multiple phoenix checks, credit scores, CCJ checks and similar trading name checks.

  • Provide DGCOS with a minimum of 10 customer references (of installations carried out within last 12 months) who will be independently approached for quality assurance purposes

  • Provide DGCOS with a minimum of 3 supplier references who can be independently approached for quality assurance purposes.

  • Provide DGCOS with a copy of their current Health and Safety Policy.

  • Carry minimum insurances of a) £2m Public Liability b) £10m Employers Liability.

  • Provide every customer with a Written Contract (to include Terms and Conditions).

  • Provide every customer with a Written Guarantee.

  • Provide every customer with Deposit Protection Insurance (where a deposit has been taken - up to a maximum of 25% of the contract value).

  • Provide every customer with an Insurance Backed Guarantee.

  • Comply with building control regulations on every installation deemed necessary.

  • Allow DGCOS Inspectors to inspect any installation deemed necessary.

  • Allow DGCOS to send every customer a Satisfaction Questionnaire.

  • Submit to the legal jurisdiction of DGCOS and the Ombudsman.


  • Every customer is automatically sent a Satisfaction Questionnaire and pre-paid envelope.

  • These replies are entered into the DGCOS performance system and results monitored.

  • Minimum standards set in each category and alerts set off when ratings fall below minimum standards.

  • These scores will be available to view by the installer and comparisons of performance with whole membership.

  • System automatically picks up low scores and identifies relevant salespeople and failing fitting teams etc.

  • Annual review of credit checks and public/employer liability insurances.


As soon as you introduce DGCOS as part of your sales presentation customers instantly know you are different from the competition.

Clive Powers - Radcliffe Glass & Windows
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