Remember your contact lenses for Mamma Mia!
Double check the weather too (likely dry but cold)
Depart 4:22 PM
Direct train from Egham to Waterloo
Arrives 5:03 PM
Google Maps Link from Waterloo (10 minute walk)
Travel from Waterloo to Charing Cross station (Northbound on Bakerloo or Northern line).
Reservation at Colonel Saab is at 5:30 PM
Finish dinner by 7:05 PM
Google Maps Link from Colonel Saab (10 minute walk)
Arrive at Novello Theatre by 7:15 PM
Show starts @ 7:30 PM
Curtains down at 10:10 PM
Walk across the bridge back to Waterloo
Depart 10:50 PM
Direct train from Waterloo to Egham
Arrives 11:27 PM
There's plenty of later trains too!
Hopefully you know this one :D