If it's from scratch i would say anout 2 weeks but if unhave learnt it all going thru it qgainnis like 2days max C1 4days if u remember gcse C2 same as fp1 maybe 2-3weeks
It took me just under a month to get through FP1, it's a very easy module. C3 and c4 took a bit longer. I didn't self study for c1 and c2, it took ages in school.