I have spent my life trying to see one close up but all I have managed is to spot one flying from place to place at some distance. I identify them only by their call. When much younger, I would deliberately go out of my way to see them, check their colouring and even watch them visit the many nest sites near my home. But nothing!
I understand your pleasure in spotting two of them.

Try sucking whilst you brush ........ works for me 

A couple of days ago I gave our vehicles their first really good scrub in nearly a year. Being damp Brittany there was a huge amount of green furry stuff around all the window seals and crevices along the trim strips. Pretty much wore out an old toothbrush getting rid of it. Two days of gleaming again and now the blue tits have taken an interest in the mirrors. They sit there admiring themselves and crapping in delight. Covering the doors and both mirrors on both vehicles. If I break down and clean it off I'll have to put bags over the mirrors to stop this behaviour. My fault for washing them in the first place.

Only ever seen one once.

When our barn was being renovated, the wall height was increased by 1m to give better headroom on the first floor. During the work the windows had been removed and we noted a pair of black redstarts regularly entering the top floor via one of the window holes. So one day I ventured into the construction site that was the first floor and saw the pair heading to and from a niche in the wall where the original roof beams had been. And there in the niche was a nest with a near fully fledged cuckoo.