Hi Guys, sorry for the delayed reply, some personal life events took precedence.
I borrowed a 1000 mm f5 newt from a mate to play with last night.
Crikey, not easy for this refractoholic though!
Couldn't get it to focus for visual with my diagonal & eyepiece, so gave up and attached my camera instead.
Trouble is my QSI is a heavy beast, way too heavy for the crayford focusser anyway - I could see it slipping as I watched!
..And the tube is so long that it will easily hit my tripod's legs.
Long story short, I abandoned it and put my small frac back n and was imaging within 15 mins.
Think I'll look into the barlow suggestion, (thanks Marc) and also try using the original flattener that was supplied with my WO - as it's not a reducer, which gives me a FL of 770mm @ f7.0
Stay tuned