revs1972 ~ You do need that second qualification! My nephew did it and it cost over £100 for a day’s course with a certificate guaranteed at the end of it. You then need to take the second CSCS test (£19:50), for which the revision books/DVD’s are a little cheaper on Amazon than on the official CSCS site. Once you have the two certificates you can then apply on-line for your card
There is a lot of useful info on the CSCS official website Particularly which card you need for which occupation, which second qualification you will need, and where to find the training companies offering it. The website itself is a little difficult to navigate but with some patience you can find out all the info you need there. Beware of the commercial companies offering to take you through the CSCS card application process, there are the inevitable mark up’s that these commercial enterprises charge for a process which you can do yourself on line.
Good Luck!