Hello Fanjo! nice to see you in here, you sound as though you are having a bit of a wibble. I have those too - same age situation although I'm 3 years further down the line than you and DS will be 4 very soon
For some obscure reason I am still attempting to have DC2 (mostly because DH always wanted 2, I think) and not going so well at it - so I have wibbles sometimes too, but then think well DS is very happy as he is, although he seems to like other people's babies, he's never yet asked why he can't have one - and since we live in Australia, a second DC would be a major investment in terms of plane tickets home back to the UK. I think "que sera, sera" and leave it at that.
I also have 2 siblings - one of whom might as well not exist for all the use he is - and one of whom I get on well with now but didn't until we were in our 20s. As a child, I would have loved to have been an only. Now, having emigrated, I am glad my sister is still in the UK to be there for my Dad - but if she wasn't, and I was an only child, my Dad might have come with us anyway so it's all swings and roundabouts.
CMOTD - fingers crossed he doesn't go for the politician option then! 
Have you ever seen Amazing girl, completely mute, trains horses brilliantly. In this clip she is riding without reins or saddle and of course no verbal commands - amazing communication she has with the horse. Those riders in your clip have serious danger ishoos! 
Scout - sorry your sister is being a bit of an arse - hope she gets over herself quite quickly and doesn't put a damper on your enjoyment.
And you may have missed some of the faster-living areas of the UK... 
anyone, or is it a touch early for you all?
instead then.
We had a horrendous start to the day, temp climbing to 38 deg C in the shade
with a hot breeze; and then about 9:30pm, a sudden shift and cold air started blowing around - thank goodness! So I switched off the fans and opened all the doors and windows (they're all screened) to blow out the heat. Phew! Nasty foretaste of what is to come though...