Back in 2010, there was no kit available, at least not in the Netherlands. You could order the PCB’s directly with Bernd, and Reichelt in Germany did have a kit with all the electronics available. Unfortunately, at that time Reichelt would not deliver to the Netherlands.
So I had to order all the components at other companies such as Conrad and Farnell. The Si570 was supplied by SDRkits (https://www.sdr-kits.net).
The first problem I encountered was that I could not find a certain type of large unipolar capacitor, needed in the transmit circuit. At least not in a size that would fit on the PCB. I decided to use bipolar (tantalum) capacitors instead, mounted anti-series. The capacitance value was twice as high, and due to the series connection, the resulting total capacitance was about what it should be. I had to add a bleeding resistor to ground at the middle point, to avoid damage due to wrong polarity.
Apart from that, there were no major problems with assembling the unit.