When grabbing the list of supported channels from tv_grab_uk_rt, the <display-name> of freeview.hd.channel4.com is "Channel 4 HD" making it indistinguishable from hd.channel4.com. Looking at other Freeview channels, they are distinguished by a "[Freeview]" string.
It looks as if the "[Freeview]" string is missing from the <display-name> of freeview.hd.channel4.com.
Updated in v1.258 of uk_rt/channel_ids