But concerns were raised about how the law would affect UK troops working alongside non-signatories in Afghanistan.

In most cases I'd agree that they shouldn't be used due to civilian risk after any conflict. However I feel they should still be allowed when bombing airbases. It makes repairs much slower which is a tactical advantage and as it's a large military target, there won't be any civilian casualties afterwards. Clearing them up at a later date wouldn't be too hard either. One big crater from a conventional bomb can quickly and easily be repaired.

I'm always amazed at how 'fair' we try to be by banning nasty weapons and following rules of engagement when our enemies would surely not do the same?

The only real problem is when they do not explode within a reasonable time frame. Though they can be fitted with timers to detonate within a few days.

I don't see that as a problem with airfields. It's a relatively small area to cover while clearing them, it just takes time.

Airfields are not the only target. They are used for attacking large areas and area denial.