…that I'll be able to swap my existing cassette straight onto my new wheel that I'm picking up today. I currently have a SRAM cassette on a no-name, factory fitted hub and my new 'light touring' wheels have 105 hubs.

Before you ask, the cassette is in good nick, I changed the chain in good time.

Ta.

Are the hubs new 105? I.e. 10 speed?

Even the new ones aren't 10 speed specific, only the original DA 7800 and Ultegra 6600 ones were.

So, yes it will.

The shop know I've got an 8 speed cassette. Truth be told I thought I had a shimano cassette until I gave the cassette a really good clean at the weekend and saw for the first time the words 'SRAM lockring' 😳

You'll be fine.