2 lenses maybe
50f1.4 IS L USM with modern optics, weather sealed, 35LII build quality
50f1.4 USM with double gauss optics, new coatings, and (pray to deity of choice) ringUSM, 85f1.8 build quality (which is perfectly good enough for most)
If we get
50f1.4 IS L USM @ £1500
50f1.4 nanoUSM @...