@bernieraffe 

Hi

The extender's signal source is the router's Wi-Fi, but the extender will have its own Wi-Fi name.
If you have not purchased it yet, it is recommended that you contact the router's support to confirm whether the router supports mesh and whether there are any extender recommendations that support mesh, because there is only one Wi-Fi name in the mesh network.
If you have already purchased it, you could try changing the extender's Wi-Fi name to the same as the router's to test whether it meets your needs:
Via Tether APP, please refer to How to change wireless settings of TP-Link range extender on Tether App.
Via Web Management page, please refer to How to change wireless settings of TP-Link range extender on Web.

  @Joseph-TP 

Thanks very much for your help, I havn't yet made the purchase so I'll get in touch with my router supplier as you suggest.