Where are you flying from? That's sure not a lot of time, but you can see the highlights if Beijing and the wall.

home base?

it would be fun but rushed and tons of jet lague probably...

Just the right amount of time to see Beijing (and the Wall).

You may have 6 days off, but you have just 4 days on the ground in Asia. You can do it, it will be exhausting but exhilarating. If you can take just a couple more days off, it will make it more worthwhile.

I live in Valencia, Spain. Unfortunately, I can't take more time off. I'm a teacher and my boss wants us back on the Thursday

If the flight is affordable and you have limited time, i say go for it!

I agree with ddgunbug, my friends did it last year, went to Shanghai as they had free lodging there.

I've just seen how cheap the hotels are there - wow!

I read that you shouldn't go at Easter - why is that? Because everyone goes? Or is there something going on then?

Nothing wrong with Easter as it is not a holiday in China.

Looks like I'm going to find it tricky to get a visa for Easter. The other possible option is September - is that a good time to visit? Still only for a week.

Why would it be tricky to get a visa for Easter? It is over 3 months away and it takes a week or two to get a visa.

Because I have to go to Madrid to get it and I can't take that time off work. It's one visit to apply and another visit to pick it up, if I understood correctly. I just can't take that time off and I don't like the idea of spending 70 euros on the train each time. The only way I could do it is if I could get the visa here in Valencia, which doesn't seem to be possible. In September, I'll be back home in London, so it'd be easy to sort out the visa in just a few hours with no travelling involved.

There may be companies that can get you your visa without you having to go there.

Normally you use visa agents or the visa center. Check the visa center website on the most efficient way to do it from where you are.

I can't see any other way to do it here in Spain. I've seen on Wikipedia that there is sometimes a way to get a visa on arrival, but it doesn't give any more info...

No such thing as a visa on arrival.
Here I see a link about applying by post: http://www.visaforchina.org/MAD_EN/

I've checked out the visa agent options and they're all too expensive. We're on a serious budget and were only going to go at Easter because we found an amazing deal on flights. We'll go another time when we're based back in London and it's easier to sort everything out. Thanks for your help!