For helpful information on SVFR, and much else besides, see Irv Lee's FAQ at
http://www.higherplane.flyer.co.uk/faq.htm
(SVFR is dealt with in numbers 14 and 15: note that a PPL without an IMC needs minimum visibility of 10 km to fly SVFR)
Irv's post-PPL seminars are well worth the money.