I should give sunflower seeds a go. I've found when I have shoved out half a coconut this winter the birds like it a lot more now I hang it on a branch of elder from next door's garden rather than on a pole, so maybe I can tempt some of the local flocks.

Goldcrests are so pretty! I have seen them in the past, but not here. I am glad that yours recovered from its shock and was OK. Fortunately, it is generally fat woodpigeons who hit my windows, which seem robust enough to walk away.