Update: think I have found the part causing the problem... and if I am right then thank god its not pinking!.
I had a new manicat fitted about 3 months and the garage gave me warranty on the part and labour...
This morning, started the car up for work, it was cold and heard a loud metalic rattle.
Instantly I thought of the exhaust bracket that holds the exhaust to the gearbox, this is about the only part I didn't check.
I looked under the car and the new shiny bracket (round metal thing with two holes in it) was not bolted to the gearbox, i know where it bolts to as I saw this when the new manicat was fitted.
The bolt has come loose and come off, the bracket isn't damaged, looking at the bracket - you can see it that it has two bits that the bolt goes through and the mounting hole that it secures to on the geabox goes in between these two wholes with a shiny bolt right through it to tighten it to the gearbox mounting plate.
I can only imagine that over the past few months - the bolt has been unscrewing it-self under vibration as now there is no pinking type of noise, just a metally rattle.
It's gone to the garage now to get a new bolt put to secure the exhaust to the gearbox to prevent too much distortion under load (dont want the flexi breaking again).
So, hopefully - the noise wont return when it's proper secured
.
Will post an update when I pick up the car later this afternoon... oh and it's costing me £20 labour as I cant wait till next week to get it done by the garage who fitted the manicat.
One last thing, it all makes sense now too as when the new manicat was fitted, i could feel more vibration through the car under load upto about 2000rpm, garage said it was the exhaust bracket mounted to the gearbox that causes that and you cant really do much about it other replacing all the engine mounts and gearbox mounts when they have worn too much, anyhow - the mounts look fine so ill go with it for now...
Fingers crossed!