Mechanic had a look at it today. I didn't get a chance because working loads of overtime lately

It turns out one of the exhaust manifold bolts (genuine OE Ford) snapped. Nut and washer gone. The front one's near the cambelt also came loose. Tightened them up and boom, ticking gone.

New M10 bolt being installed next week so manifold off and on again....fuppin 3rd time this year

I think a major contributory factor to the breakage was the rose joint on the stage 1 turbo bailey hanger. It wasn't supporting the weight of the T34 and exhaust so I guess, it stressed it out too much. Loads of info on here about that.

Next step is an RS500 damper and spec-r 4X4 head bracket.....only £300 +