Thanks one and all for your comments.
Yep the AP QUAD reducer is not cheap...
...but, hey, if you want to make an omelette... you gotta break some eggs, even
if AP/Taka require the golden variety.
Looking at the forecast, a colour version seems unlikely this Eta season, but
thankfully, Ara and Scorpius are rising
P.S. I have imaged Eta before,
maybe once or twice here 
but it's always nice to use it as a standard candle
for your new gear