Yes, CEL-FI signal boosters are compliant with Ofcom's regulations and are legal and license-exempt in the UK[1][4]. These boosters have features such as self-optimization and auto-adjustment, which ensures that they do not interfere with other radio equipment or disrupt mobile networks[4]. The Amplifi-Qx system also uses CEL-FI boosters[3][4]. Stella Doradus is another brand that manufactures Ofcom-compliant mobile signal boosters[7].
Citations:
[1] https://www.ukconnect.com/post/a-deep-dive-into-ofcoms-signal-boosting-regulations
[2] https://totaltele.com/according-to-nextivity-mobile-signal-boosters-come-of-age-thanks-to-relaxation-in-ofcom-licensing-laws/
[3] https://www.signalsolutions.co.uk/regulations/
[4] https://www.signalsolutions.co.uk/blog/guide-to-mobile-signal-boosting/
[5] https://www.ofcom.org.uk/spectrum/radio-equipment/proposed-changes-to-mobile-phone-repeaters-regulations/
[6] https://www.uctel.co.uk/blog/legality-of-mobile-repeaters-in-the-uk-can-you-use-them
[7] https://www.stelladoradus.com/blog/ofcom-compliant-3g-4g-5g-mobile-signal-booster/
[8] https://mobilesignalsolutions.co.uk/which-signal-boosters-are-safe-to-buy-in-the-uk/
[9] https://www.ispreview.co.uk/index.php/2023/10/ofcom-uk-to-soften-mobile-signal-booster-requirements.html
[10] https://www.ofcom.org.uk/phones-and-broadband/coverage-and-speeds/new-rules-to-help-you-get-a-better-mobile-signal-indoors/