I'm afraid I posted 'Engine revs and can't get in reverse' but I now have an update that corrects that description of the issue. Best I can do is paste the message here and maybe it will make sense to someone:

2005 Honda Accord Vtec Executive A, Petrol, 2354cc. Automatic.

"Hi Les, so basically after driving home and when I put the car in park when I was trying to reverse into the drive it got stuck in park and made a really loud revving sound and jolted forward. Freaked out turned it off and on again where it did same again. After a couple more times stuck a key in the manual slot and eventually got it on the drive and when I put it back in park it got stuck and made revving noise again. Tried several more times. After half an hour later it worked fine! The next morning it was fine, when I left work it was fine. However got home and tried to put in park, it jolted forward got stuck and made revving noise again. I ***umed it was something to do with when engine was hot? However Wed morning when tried take it to garage it was cold and stuck in park. Mechanic came over Thurs and it happened to him as well. When he came on Friday it didn't happen and drove fine. At the garage is got stuck again but he said it wasn't revving?! And this is all on top of the massive rattling under the engine. He said he's stumped"

Not sure if the rattle is related but I do have a short video with it.

Many thanks. (And apologies for having to post a second time)

 

might tell the mech if adjusting the rocker arms may help fix the engine. its got a heck of a rattle. this could be the base cause of the trans stuck in park and the jolting.