central locking not working with keyfob

after some help again,

i have come home from work tonight and parked up, i have tried to lock the car as normal with the fob but it wont lock. the red light flashes but nothing. i have tried the spare key but this is the same. i can lock the door with the key and this will activate the alarm/ flashing light on the door, but it will then not unlock with the fob either. when i unlock the door with the key i have to put the key into the ignition quickly or the alarm goes off. if i use the toggle switch inside the car i can lock and unlock the doors. this has happened once before just after i got the car but it fixed itself over night. 

any ideas why this has happened? 

thanks.