The telephone number +44 7775 106684 is being used by NHS Wales to send out Track & Trace service texts. If you receive a text message from this number you can be confident that this is not part of a scam.
I never signed up for Track&Trace (have an iPhone 6). Feels like a scam. pic.twitter.com/Qu00gwGds3
— Radha Nair-Roberts (@bratdha) October 9, 2020
There are several sources online that confirm the validity of +447775106684 as a genuine communication from NHS wales:
Government of Wales Test Trace Process