Fuse types

[sceh]

My aircon does not work and I assumed it was duff but when checking other fuses I find that two fuses (33 and 36) are not even present. Fuse 40 is and all three are for the A/C according to the book.
FIrst problem - they are called HTR SUB1 30A and HTR SUB2 30A (33 and 36) and HTR 40A for number 40.

So, what does HTR stand for and where do I find this type of fuse (B/T) since no-one seems to sell them.
Do I need all three or is the aircon not working for another reason. The car is 2004 and it could be that these fuse emplacements are for a previous version.

ANd who oh why does the manual not mention that there are two fuse boxes and not just one? Mind you, the one under the dash is so inaccessible it may as well not exist...