8sp or 11sp, 26" or 700c, disc or rim?
Will this greatly affect the cost of sending the wheel?
Depends on the exact size, weight and value.
If you take it to a post office, its £12 for ParcelForce, covered for up to £100. Add £5 if you need cover up to £500.
Or CollectPlus would be about £5 (covered for up to £50), you can drop it off at a local shop. But that has a max size of 60x50x50cm, you might struggle to fit a wheel within that.