put it this way, i have a barge pole, and it is not going near your alarm.
I shall explain.
Radio alarms by deffinition are very good, no wires, quick to install great, nice and easy.
Now read that again. NO WIRES, as it is radio it becomes suseptable to other radio frequences and interfearance.
yes they are on their own "special frequency" but that does not mean to say they can not suffer from interfearance.
Q. If a radio detector plays up what can you do ?
A. Nothing because they are radio you can not see if there is another radio signal interfearing with it.
When a professional radio alarm is installed they are supposed to test for field strengh to see is it suitable (most dont) they will also "not work" in new houses since the dry wall is foil lined and blocks the signal.
Friend of mine (alarm engineer) put one in a new show house, wouldn't work, call to manufaturer, Help line man said is it new house? "yes" forget it said help line.
to meet the B.S. 4737 standard radio alarms have to be "class 6" most are not (its nothing to worry about but alarm companies will not touch anything that is not class 6, because insurance companies do not accept them)
You are wondering about the battery in the bell box, with radio detectors you have to change all the batteries once a year, when do they send a low battery signal, when you are in bed asleep or on holiday that is when.
Because it is your alarm do you really change the battery strait away, yes? well what about that smoke detector you have with no battery?
Most people with diy radio alarms with all good intentions forget to change the batteries or "will do it later" and never do.
Even hard wired alarms have to have the control panel battery changed once every five years to ensure reliability.
I have nothing in particular against any brand of radio alarm, I after hearing just a few stories (they are true) hate all of them.
They also seem to cost more in the long run since as i said, every year you have to change the batteries with good quality (you know the brand) batteries which can be £2-3 each, now multiply that by the number of detectors and tell me its not expensive.
I would suggest always have a hard wired alarm, as yes they take longer to install but are much less hassle and cheaper in the long run.