Been offered a Scott hardtail frame for my son to build up using my spare components but it’s only got v-brake bosses on the rear and all our parts are disc only. Do any component manufacturers do some kind of adaptor to allow use of discs??

If its allot with flat drop outs an AtoZ should do the trick:
http://www.woollyhatshop.com/brake-spares/disc-brake-adaptors/cat_58.html

There’s a few. Lots of people suggest the A2Z so it might be fine but I think it’s a bit of a poor solution. I’ve used the Specialized one a couple of times which work really well, it bolts to the dropout and the brake boss to spread the load. For both these you need a reasonably large flat dropout. The Specialized one is out of manufacture so its probably ebay only.

I used the AtoZ for a few years without problems.

The A2Z works well but only on frames with the right sort of dropouts (flat plate type basically).

On my CX:

Many thanks to you all for that, going to take up the offer of the frame as it seems a viable proposition now 🙂