Found 3 solutions at Whitworths... for A$170 the complete Shurflo unit ( taps, shower head etc) in a 'box' that rebates into the transom; for A$55 a showerhead and hose... bit of chrome and only 1.5m of non reinforced hose! and thirdly a plastic, no chrome showerhead and 2.1m of reinforced hose for A$25.
Yes folks the last option selected... and it works fine.
BTW, discovered that the originally fitted Shurflo showerhead can be dismantled to replace the O rings when it become dribbly. Using a fine hooked pin, simply pull out the centre part of the spray nozzle. This reveals a small stainless nut and washer which can be undone with an appropriately small tube spanner. The rotatable head is then withdrawn revealing 2 O rings.