Did you go, SS? Was it a genuine booking and, if so, did it pass without incident?
In addition to the advice from others, I recommend:
1. In the case of cash payment, ask the punter to send you a picture of the cash with the notes spread out so that you can see the full amount and with a note saying the day's date. (Only yesterday, someone wanting me to travel to Hull from just outside Leeds - where I was located - and claiming that money was no object, he had loads-a-cash at home, I only had to name my price, hung up on me the second I asked for this!)
2. For further proof of address, first ask the punter to text you his full address, then ask for a recent bank statement or utility bill as proof of address. (Once, someone who had texted me his address then "doctored" the address on his bank statement. To be exact, he overwrote the door number with the one that he'd texted me).
3. Ask who will be at the property.
4. If you drive, ask where you can park.
5. Ask if there are any strong smells at the property such as cigarette smoke.
6. Ask if he has any pets - a dog that might come charging at you, for instance.
7. For a hotel outcall, ask for the booking-name and room number and then call reception to check that the guy really is there.
8. For all bookings, check the guy's phone number both on SAAFE and on National Ugly Mugs
My advice comes from experience, SS.