I see the Satbeams website has published a footprint for HB13G - looking at it, it would appear that compared to the old HB13C it replaced, it's "core" footprint is skewered a bit more to the north-east to provider a little stronger coverage towards Poland and the southern Baltic sea area at the expense towards the north-west - the EIRP level at my location for HB13G is given as 50dbW compared to 51dbW for HB13C, which would tally with a 1db reduction in SNR I've been experiencing. Looking at the 52/51/50/48 dbW contours they don't extend as far north & west across the UK & Ireland as the old HB13C used to. This does make some commercial sense on Eutelsat's behalf though - reinforce reception across Poland as the position is a Polish "hotspot" at the equivalent expense in an area where there are very few channels aimed at a DTH British or Irish audience.
A quick look elsewhere on the Satbeams HB13G footprint suggests power reductions for reception of HB13G compared to HB13C in the Azores, Canary Isles, Iceland, Istanbul, Moscow with a slight reduction in power levels covering most of the Arab peninsula, Iran & Pakistan (except for around Yemen & Oman).