You could put another hive there I'm sure. HOWEVER, despite my Forum name I'm not under any illusions about the suitability of keeping bees in a garden, esp. where neighbours are involved. When it's going well it's great, but you definitely need to keep an alternative site in mind for if the bees have a change of character.
30ft is OK for most occasions, but nothing like far enough to keep away from really angry bees... so I would definitely have a back-up plan just in case they lose their temper. For example, if they become queenless and defensive, if you open up the hive in unsuitable weather, or if you accidentally bump the hive or otherwise fall out with them, guard bees are quite capable of hassling you for 100 feet or more. Hopefully it wouldn't happen, but unfortunately it's a fairly common cause of problems with garden bees, esp. in their second or third season when they're really going strong.
Also, if you "walk them back with you", ie. progress back to the house with a few hangers-on still buzzing around you, they are quite likely to hang around the house and continue making their point next time you go out the back door! So if they're a bit roused, it would be prudent to wait a few feet away, possibly wafting some smoke over your bee suit, until they disperse, rather than risk them following you about the garden and remembering their last point of defence.
Having said that, I greatly enjoy having bees at the bottom of my garden... It's a 140ft garden though, and on the one occasion when one colony lost their temper they defended the bottom 60ft or so quite vigorously for several days, i.e. I couldn't get past the shed without a bee suit. With extra space and a new queen they settled down very quickly, but this isn't always the case - some colonies just aren't well-behaved. Hence the need for a backup plan!
