You have to build a little pyramid… the 10 ohm capacitor at C1 and the diode get pyramid’ed up against a resistor that’s added, this smooths the readout in the circuit and makes it stable. Can’t remember at the moment what value of resistor is added and there are some other ways to do it but the little pyramid is the most interesting way. 
A post from djozz along with a picture…
To quote Jos… “First I soldered C1 vertical on its ground pad, then I unsoldered D1 from its led+ pad and soldered it leaning against C1. Then the 10 Ohm resistor was soldered between led+ (the old and now vacant D1 pad) and the top of the pyramid. The top was then filed as low as possible without damaging the components.”