Hard to say but the boiler isnt 10 yrs old if you make a note of the serial no and ring alpha boilers they will tell you when it was made, and i would guess it will be 2003 -2004
it is possible the fault will come back, i have found if there is dirt in the system this also causes the diverter valve to fail or not work correctly, so it probably will happen again
If you look at the top nuts coming off the plate heat exchanger they look the same colour as the diverter valve which would indicate it hasnt been replaced, your boiler isnt 10 yrs old probably about 5-7yrs old but some of them have been very troublesome and some have not i personally have...