The only resource that comes near that sort of volume of individual questions is the Tutors Verbal Reasoning CD No. 1 (Item 7 on this page): http://www.elevenplusexams.co.uk/cd/
, which has 50 questions of each type.
However, on-screen practice isn't ideal for codes and if your son really needs that volume of practice questions on any code type, he hasn't absorbed the technique.
Re-visit the method for solving these first, and then re-use some questions from earlier - children do not remember the answers after a few weeks. You might also buy a couple of new books and simply use the questions you need from them over the next few weeks.
BTW, SD Type 32 is really not relevant for GL Assessment 21 types.