Hi Sharon
First of all, I would urge you to consult your GP or NHS Direct about medical matters. They know a lot more about these things than I do!
However, I do think it is worth wearing DVT socks. Research has shown that they can reduce the risk of developing deep vein thrombosis by as much as 90 per cent. They work by compressing the leg from the knee down, allowing the blood in your legs to flow properly. If you really don't want to wear them, I'd suggest making sure you drink plenty of water and avoid alcohol, and make sure you get up for regular walks and wiggle your toes from time to time.
As for the temperatures you can expect, April is a very good time to visit China as it will be warm and sunny. Daytime temperatures average 50-60ºF but you should take a lightweight waterproof jacket in case of the odd rain shower and also a warm sweater/ jacket to wear in the evenings.
Lastly, your flight from Heathrow is direct to Beijing.
Have a fantastic trip!
Kind regards,
Olly, your editor