Cable clips

B&Q sell them (I think) - although I might have got mine from TLC.

Meter tails 11mm OD, so:

Never seen meter tails clipped in my whole life...

Usually (IME), if the meter and consumer unit are immediately adjacent, clips for tails are not necessary. (The DNO/meter operator almost certainly won't have used clips between the cutout and meter and they're not yours to mess with so notionally, you shouldn't clip them either). If meter and consumer unit are further apart (up to 2m length of tails notional max.), then tails usually go in 50 x 50 plastic trunking.

However, what Tim says (except I would go for white, not black!).

On the whole no, but then they are generally installed close to the meter and probably not long enough.

But when I moved my CU around a corner I clipped the tails.

Routing it through trunking sound like it would have been awakard and a bit faffy/messy for mine.

I asked a similar question here and used 12mm plastic P clips secured with round headed screws

Ebay was cheapest for the few I needed.

I have often clipped meter tails. TBH the last lot of tails and earth were clumped together and held in place with SWA cleats that I had on the van. It did not look too bad (I dressed them into place not a random grab of the cables) and they were very secure.

Adam