CasetheCorvetteman wrote:
You can can number 3 too i reckon, you wouldnt get good pressure when cold and none when hot if the pickup came out, unless you sump is getting low when the oil heats up.

Have you checked under the filler cap to see that all your oil isnt staying up there and not draining back? Might be a very very long shot, but anything is worth a look at this stage.