Just use bleach.
For fsg etc I always wack a bit in.
In my van I carry all purpose cleaner, washing up liquid, bleach and cream cleaner.
All usually Asda smart price or similar cheap supermarket brands.
Mix them all together in spray bottle for a lovely blend of cladding/Conny/fsg cleaner.
Simple supermarket ingredients, no need for virosol/tfr/hypo and all that jazz
All purpose cleaner is a degreaser like G101, flash or virosol but a bit thinner as it's cheaper, just use it neat .. it's like 25p for 500ml.
Bleach is well like weak hypo and cheap as chips
Washing up liquid is a degreaser plus it adds a nice foam to allow the other ingredient a to stick and dwell.
Cream cleaner is abrasive so good for restoring uPVC and I've found that slapping some on the brush head for first cleans and cladding works really well.