(04 Nov 2023, 9:12 am)Alison71 wrote My son left a bag on the 71 from chester le street to Seaham, is there a number for Gateshead central taxis lost property?

Not sure if they're valid/current, but I've managed to find the following contact numbers:
0191 466 1360
0191 469 9999

If you have no luck with either, then try Nexus: https://www.nexus.org.uk/contact-us/bus

Good luck!