have heard of people using bells tied to the hadle. Same idea but cheaper I guess.

yeh i was going to do that, but i need some helping actually teaching them how to do it & you get a step by step guide! its only £15 (ther eis one for £10 but it was sold out) and the bell is water proof so you can put doggy (once taught & doesnt need your help etc) in the garden and shut the door.........and hell ring to get back in too! lol!!

Yes....that is exactly what my lot would do....
We leave our keys, on a long key ring, in the door, Cosmo jingles them when he wants to go out, he hits them either with his nose or with his paw...if he's desperate he hits them a lot!!! Thing is, he will do it if he thiks he's not getting enough attention, or he fancies a treat (he gets a reward when he comes in from spending to reinforce recall etc and cos I love him ) ..so he'll rattle keys,go out, look at you, then do a zoomie back in and sit beautifully waiting for his treat as I wander in mumbling.He doesn't get one in that situation! Our FCR pup that we walked used to do exactly the same....