Easy enough to do with a soldering iron of some description and a steady hand.
First get yourself a repair kit or two from China for a princely sum of £2 each.
A pair tweezers or a cheap phone repair kit will come in handy for handling the switches.
Inside the kit you'll get three micro switches and a hard shell case.
First pop the key blade and horseshoe shaped section away from the buttons.
Theres a little square flat lug section on the back of the key.
NOTE: Don't loose the little square block attached to the horseshoe shaped plastic, this is the immobilizer chip.
Split the button casing to expose the three micro switches and circuit board.
Circuit board is held in with some little plastic lugs on one edge, gently prise it away from the case.
The switches are "surface soldered" if thats the correct phrase. Soldered on the side you see , two lugs either side of the switch and not on the underside.
Use your tweezers to apply slight pressure to the underside of the switch as you heat the solder. Once one side of the micro switch has separated and lifted , do the other side of the switch.
The new switch can be positioned using your tweezers, there should be enough solder remaining to heat the switch lug and make a good connection.
Plenty of soldering tips online. I used a bit of "solder removal flux" to tidy and prep.
As they say, once the new switches are fitted, reassemble in reverse order.
(the eagle eyed will spot i removed the battery holder, but this isn't necessary )
RIP 
