The best summary on the website is hidden in the background information for applicants to become the Senior ICT Technician
(I wish I was making this up...)
In Years 10 and 11, all students take IGCSE courses in English and English Literature and GCSEs in Mathematics and French. Many students also study for GCSE Statistics. They also take either an IGCSE in Information and Communication Technology or a GCSE in Computing, and either IGCSEs in all three separate sciences or a single GCSE in Additional Science. Students, constrained only by the requirements of the National Curriculum, add to this a number of GCSEs from those subjects available in Years 7-9 and have a further compulsory syllabus consisting of Physical Education (including Games), Personal Development and RE. For the teaching of French and Mathematics, students are placed in one of four sets according to ability. There are carefully devised assessment and reporting systems. Extra-curricular opportunities exist to take GCSEs in Spanish, Physical Education, Astronomy or Geology, the latter two subjects in partnership with another local secondary school.
I think that there is a difference between subjects and (I)GCSEs. English is one subject, but two qualifications (Lit and Lang) and Maths (except the lowest set) is the same as it also includes Statistics. Therefore you have ten subjects with twelve qualifications.
The number of additional choices is 5 with Additional Science, or 3 with Biology, Chemistry and Physics. As a result the breakdown is as follows:
1. IGCSE English (Language)
2. IGCSE English Literature
3. GCSE Maths
4. GCSE Statistics (except bottom maths set)
5. GCSE French
6. GCSE Computing or IGCSE ICT
7-9. IGCSE Biology, IGCSE Chemistry & IGCSE Physics or GCSE Additional Science and two options from Year 9 subjects
10-12. Three options from Year 9 subjects
Plus any of the extra-curricular options (although I think that they like to limit the number of these, for obvious reasons).
The bit about Technology on the website dates from the old options list which included a choice between short course GCSE ICT (first year, with second year supervised free periods), 'full' GCSE ICT or short course GCSE D&T (if you wanted to do 'full' D&T you had to do it as an option, as you have to do now).
Incidentally, the other updated information about GCSE options is hidden in the 2010/11 prospectus at http://www.crgs.co.uk/the-school/prospectus
, but this doesn't explain the choice between ICT and Computing.