In December last year (2018) G0MJW, M0EYT and me (PA3FYM) were involved in designing a LHCP-dual band 2.4-10 GHz feed. Inside this 'love triangle' Mike MJW appeared to be the CST modelling hero (per default ; -), Paul EYT the CNC hero and I (modestly) the circular polarisation (CP) feed point guide to let the patch really produce CP. Result seems to be a good performing LHCP patch (for standard offset dishes with f/D = 0.6). Placed in front of a dish it produces RHCP towards the 2.4 GHz RX antenna of Es'hail-2.
Only issue to be dealt with is the transition of the (circular) wave guide for the right aperture for a f/D = 0.6 dish. One solution is to buy a 'wrong' (cheap!) DRO 'rocket' LNB, remove the dielectric lens ('polyrod') and throw the remainders in the dust bin. Another approach is to make a dielectric lens. My/our first attempt is/are here: https://tinyurl.com/y75htz9c