Laguna starting probs when hot outside

[bwellard]

Just purchased a V reg Laguna 1.6 16v. When it's colder outside, eg. 1st thing in the morning, the car starts fine. When the car has been sat in the sun and the outside temperature is hot (it has been recently), the engine has terrible problems starting. When it fires up the revs go up to 1000 or so and then drop as low as not even registering on the rev counter. The car judders and shakes, and eventually starts idling properly after 10 seconds or so. Any ideas?