Several wierd patches have developed on my lawn this year; they are
circular, about dinner-plate sized, all the grass has completely died
and disappeared in the middle and around the circumference the blades of
grass are all flat down and pointingt to the centre of the circle. Looks
almost like a crop-circle phenomenon... In one case, the centre of the
whole coincides with the hole where our rotary washing line stands -
don't know if that's relevant?

It's very different to the 'scorch marks' left by dog urine - I know all
about that too :-( Has to be said this is a very grotty, unloved,
poorly drained and moss-infested lawn.

Any ideas?

Thanks
David