I'm thinking it's ONCE IN A BLUE MOON but can't work out why.

I meant to add this:
Hesitate about small business centre (4)

[Chalky] CO (small business) + RE ("er" backwards).

[rab]Spot on; it's an anagram but with an M (my first) removed - it would have been harder (but still I think acceptable) to have not included the "- and only very rarely" - the definition then being the "Uncommon" which doubled up as part of the anagram.

Hmmm - Apologies - I've just looked at it and seen that somehow I missed out the B - sorry, sorry, sorry - will check them better in future.

Nothing still outstanding?
It's not right to scry the lawnmower. (6)
He'll summon you for taking a bad grip on a faulty reamer. (4,6)

Second one would be GRIM REAPER?
Sorry, it hit me straight away - I'll have a look at the first one when I'm finished what I'm up to.

Your first, Raak would be SCYTHE ?

*chuckles* I'm a bit slow - I only saw the connection 'tween the two after I'd posted my last entry.

... Is Raak hinting something ... ?