Found this post on AVCT - WORTH REMEMBERING9 Sep 2020 10:41
Foolish - my family have just been through this - everywhere site you look says too busy/no tests etc. After hours wasting time on gov websites/111 and 119 they all drove down to nearest test station and got tested straight away.
I suggest you just turn up at your nearest test station and you should get tested, with a 48 hr turn around for results though.
And yeah more than ever we the need the rapid test.