Hyundai i20, 1.4, 2011, Engine Excessive Knocking

Good day

My Hyundai i20 (130 000km on the clock) blew a top gasket, after excessive heating with no warning lights at all. So bad that the oil boiled. Done the following (all sequences and torque to fasten bolts/parts were followed iaw the workshop manual) :

1. Pressure test on head - ok, engineering company skimmed head, replaced valve stem seals and checked valve clearance. Also checked block with a straight edge to out-rule warping - fine.
2. Replaced timing chain, timing chain tensioner and off course the head bolts and head gasket kit. Everything torqued in the correct sequence and to the correct tension. Also cleaned pistons and removed any ridges on cylinders.
3. Replaced the Engine Temp sensor and thermostat (due to no warning light), Oil Control Valve (due to excessive heat of oil) and Knock Sensor. Also flushed radiator and bled the cooling system whilst filling the system with water.
4. Timing on spot. Used a compression gauge to find the compression stroke and aligned all timing marks of both OHCs and crank.
5. Replaced oil (15W40), oil filter, spark-plugs (Gap 1mm), air-filter. Checked spark plugs heat specs, which was NGK 4ZKR6B10E, Heat range of 6 and burns light tan. Checked for isolation breaks on wires by idling the car in the dark and measured each ignition coil resistance, which was within spec.
6.Re-checked valve clearance and found 2 inlet and 3 exhaust valves to be 0,05% out of spec - Ok. This also should rule out any cam-lobe and/or shim wear-and-tear.
7.Performed a compression test which showed lowest value to be 900KPA (131 PSI) with a 14% difference between highest and lowest compression reading.
8. Checked valves by rotating the engine clock-wise and checked each stroke at its end-state (very course)- checked each cylinder for intake stroke (air through inlet manifold), exhaust stroke air through exhaust (mostly - valve overlap), compression stroke (all valves proofed to be closed - turned engine) and power stroke (indeterminant - could not feel air through exhaust, but engine did not move - should be ok since exhaust valve just started to open).
9.Tested Positive-Crank-Case Ventilation Valve. No stickiness.
10 . Fan-Belt tension correct and did test with-out fan-belt to determine if pulleys are not causing engine vibration.
11. Added fuel cleaner (maybe over-doing it) to ensure that the AFR is correct. Only use 93 Octane fuel.
12. OBDII scanner results give me code P0328 - Knock Senor Circuit High (Bank 1).

Now the only other cause I can think of is that the ECM is faulty, but that would have given me a P0606 code, which is not the case.

I am out of answers. Can some-one please assist me.

Kind Regards
Steve