LED resolutely stays on regardless of pedal being on or off. Pedal works fine apart from this one minor bug. Tried replacing BS170 transistor as mentioned on other posts but this has had no effect.
Make sure you reheat the solder joints on D7 and Q5 to make sure you don't have a bad connection there, as well the connections to lug 9 on the footswitch. If that doesn't clear it up, try replacing D7 and Q5. You should have continuity from the non-stripped end of D7 to lug 9 of the footswitch; and continuity to lug 8 should be made and broken when you click the footswitch; check on that to make sure the switch is working.
Tested dry out works fine (ie passes signal) with effect on and when bypassed. the only thing I did notice was that when in bypass mode you can hear the clock noise changing pitch when you turn the delay time knob. Its really quite and I know this is part of analogue delay but is it right for it to be audible even when the effect is bypassed or when playing through the dry out?
No, that shouldn't be. As Tark pointed out, there are a few things you can do to try to get rid of that. You may also just have the clock trimmer turned up too high.