We present here a new method based on the Radon transform to model Generalised Parton Distributions (GPDs). It allows to fulfil all theoretical constraints applying on GPDs, especially polynomiality and positivity at the same time. More specifically, we show how polynomiality can be systematically restored within the framework of the overlaps of Lightfront Wave Functions (LFWFs). It provides a systematic way to extend models defined solely in the DGLAP kinematical region to the ERBL one. We then exemplify our approach using LFWFs models.