The influence of the ITER-like Wall (ILW) with divertor target plate made of tungsten (W), on plasma performance in JET H-mode is being investigated since 2011. One of the key issues in discharges with low level of D fuelling is observed accumulation of W in the plasma core, which leads to a reduction in plasma performance. To study the interplay between W sputtering on the target plate, penetration of W through the SOL and edge transport barrier (ETB) and its further accumulation in plasma core predictive modelling was launched using a coupled 1.5D core and 2D SOL code JINTRAC. Simulations reveal the important role of ELMs in W sputtering and plasma density control. Analyses also confirm pivotal role played by the neo-classical pinch of heavy impurities within the ETB.