The badge will cost £220 and the courses are around £100. New changes are that if you have a supervisor SIA badge which allows you to work on premises where alcohol is served, you need to do a refresher every 3 years to renew your badge. I think CPL training do the courses.
I used a company called CPL Training to gain my license, its a 4 day course which cost £180, I done my course in the Wallasey Sea Cadet Unit. The licence then cost £220, but if you pay for the licence on your own you can claim a little bit of money back on it. http://www.cpltraining.co.uk/training/security/doors.aspx this is the website.