had the same request just after getting the device, and was told by support that this was a safety feature to reduce accidental activations, and they had no plans to change the timer.
I would like to second that request. The timeout of the remote control drives my Mistress mad. She says it does not work properly, what idiot would design it to turn off so quickly, her mobile phone does not do that nor her iPad nor her laptop. She refuses to use it, especially as the radio signal is so weak it cannot reach me in the kitchen just a small distance away. The remote control IS fully charged by the way and the receiver is only a month old. I think the problem is, though the two rooms are adjacent and have no doors between them, they are in an "L" shape and there is an American style fridge freezer and the stainless steel splash-back of the hob partially in the way. If we had to recharge the remote control every night it would not be a problem. My car remote locking can reach into a steel box from a dozen or more meters away and that is smaller than the DreamLover2000 remote control and its only had one new battery in ten years.