Obviously any point at which you ship something to a recipient will put you at greater risk of getting ripped off than meeting in person.
That said, eBay doesn't have to be a terribly place. And they don't have an affinity to side with the buyer, either. It's just that, often times, sellers don't think to do much beside throw the item in a box and trust nobody is screwing them. When asked for "evidence", they don't even have so much as the IMEI of the phone they just sold.
If you don't sell/buy much on eBay, you are liekly at a bit of a greater risk, especially if your buyer has a long positive track record already. Think of how it looks if you, withn three feedbacks, sells an item to someone with 2k+ feedbacks and that person is claiming fraud against you? But still, all is not necessarily lost.
Take lots of pictures. Take a picture of the screen on with the IMEI showing. You can even do this if the phone is already wiped and they are in the "HELLO" setup screen by pressing on the little "i" in the bottom right. It will bring up the IMEI and ICCID (the ICCID only if you have the sim in).
Take video of yourself packing and even shipping the device if you want to be super careful. Lately I had done that with anything "of value" that I list. If the item is over $100, I will take the extra time.
Know the types of scams. Probably the biggest (easiest) scam is claiming you never got anything in the box. The pictures and especially video can make a nearly bulletproof case for you. Another common scam is claiming there is something wrong with the product. The scammer will attempt to get back all/part of their payment as a refund in order to "pay for repairs". The best thing to do here is to offer a full refund if they send you the item back. Never offer partial. And if they do end up opting to send it back, video tape yourself opening the package (clearly show it is still sealed beforehand) and make sure the phone you got back is your phone and in the condition you originally sent it.
Now, this may all seem like a ton of work. It obviously isn't nothing, but in it's entirety, it probably wouldn't take a whole lot longer than it just took me to type all of this. All that said, the last couple of phones we have sold I just opted for craigslist (unsure if the OP has something similar in the UK) because I was able to get about what I would have gotten via ebay (minus fees) and iPhones move fast. I ALWAYS meet at a carrier store, zero exceptions. Most often I am meeting on my way to or from work, so it's not really even out of the way.