The one position in the Wales team where Wayne Pivac just can't make up his mind

Change is inevitable — though that didn’t prove the case when it came to a vending machine at a Valleys swimming baths back in the day.

Money was put in but coins rarely came back.

Potentially, that machine was the most cursed in the whole of Wales.

Anyway, change has proved the order of the day for Wayne Pivac in one particular area of the Welsh team during his tenure as national coach.

Centre has proven a vexed selection issue for the New Zealander in almost every campaign he has overseen. Over 24 games, Pivac has used 12 different midfield partnerships.

A different player has played alongside Nick Tompkins in each of the past five Wales games, with Jonathan Davies, Johnny Williams, Willis Halaholo, Josh Adams and Owen Watkin making up the quintet.

Then you remember that Davies and Jamie Roberts played together 45 times for Wales, with Warren Gatland tending to operate to the dictum that stability brings success, and success brings stability.

Pivac is still working on that one. In the two-and-a-bit years that he’s been in charge, Wales haven’t fielded the same team in back-to-back matches, with injuries admittedly not helping his cause.

But let’s return to the midfield.

Last weekend, plaudits for Wales’ resolve in chiselling out a narrow win over Scotland were tempered by criticism of their back play, with plenty queuing up to point out that what had unfolded before our eyes didn’t call to mind the Barbarians circa 1973.

The centres were a particular focus of attention, despite Watkin having his best game for Wales. As well as being the only Welsh player to make a clean break, he made 76 metres with ball in hand, beat four defenders and put in 14 tackles, according to the official tournament statistics.

If that’s cause