There seems to be a glitch in Affinity photo (at least in the beta version). :( I have tried to recolor my text many times by re selecting it; with the text tool, however to no avail, I cannot recolor it even by going into the layers and effects. What I finally found that worked is as follows:
Select the layer of text you are trying to change the color of and go into the the effects section, scroll down till you find color overlay; select it and in the menu of the box that comes up, untick all the boxes on the left and then select where it says color overlay and select the color you want, then retick all effects you want and walla your color will be changed.
I hope this helps anyone who is or does encounter the same problem! :D
