don't ever go with 2nd hand tyres for the reasons given
remoulds can be fine but you need to buy from a reputable source
frankly, I'd always go new and get a tyre that's suitable for the vehicle's speed rating.
Remoulds are to British Standards now, but I guess some dodgey ones do sneak through
I used to use Colway on my Discovery (& 110CSW - 235/85 x 16), I sold the Discovery with 35,000 miles on the Colways (235/70 x 16) & they were a lot less than half worn
Plus, last September I changed the front tyres on my Octavia estate, the original Dunlops had covered almost 33,000 miles, & still had about 3 mm left
Not too bad for a heavy front-wheel-drive diesel!
As for the Speed-Rating, please make sure that you buy tyres that at least equal the car manufacturers fitments.
Strictly speaking, even allowing for the 70MPH limit in this country, if a car has a top speed of (say?, the 'gentlemans agreement' figure) 155MPH, the tyres must have a higher speed rating than this
If not, it could be seen as a 'get out clause' by an insurance company, as the vehicle's not deemed (in their) eyes to be road-legal
Especially if you do not inform them that you have made a change from the manfacturers specification, by lowering the rating of the tyres
Silly, given our speed limits, but that's the way it is.