Thanks for the advice JMAC. I started Saturday morning with the washing and found a few tricky areas: the gloss plastic between the windows had some strange marks about 5mm from each edge, along the top of the windscreen and between the rear screen and the metal work were harbouring muck, plus a definite line across the bonnet took some shifting.
The wheels/tyres must have thrown some fitment 'gloop' out to with some awkward streaks to deal with.
There was no beading at all evident so I guess no polish on the car yet.
So, after the wash I grabbed some lunch, only to find some lovely person a few doors down the road had decided to take an angle grinder to some concrete blocks, covering the whole thing in fine dust. Bah.
As he was still cutting I had to stop for the day.
So, I know the plan for next weekend....... !