I now have a sink and after4 hours of dicking around with several different plumbing and hardware stores also have the correct fittings to plumb in the waste water tank. Still no tap but after months and months of using paper plates and bowls an actual sink was a head rush. Hoping to have the remainder of the timber work finished the week after next.

sink fitted
reducer connections with an internal connector to achieve the right external circumference to match the hose
the splash-back colour Ive chosen and as yet to send away for
finally plumbed for grey water