Ian, very pleased that you saw 2 male harriers as I have only logged 1 grey and 1 brown so far despite quite a few visits at dusk and none last evening (Wed).
The male Shoveler was on Maes Llyn at 4ish but disappeared into the edge vegetation. Interestingly there was a pale faced duck on the far side which I couldn't see well enough through bins (and it kept diving) but suspected it could be the RNecked so perhaps its travelling around the local lakes.