I've suspected for some time now that my wife has been having an
affair. The usual signs. Phone rings, I answer, someone hangs up. 
She started going out 'with the girls' a lot recently although when I
ask which girls it is always "Just some friends from work, you don't
know them". 
I always look out for her taxi coming home but she always walks down
the drive although I can hear a car setting off. As if she has got out
of the car round the corner. Why? Is it not a taxi? 
I once picked her mobile up just to see what time it was and she went
berserk and screamed that I should never touch her phone again and why
was I checking up on her. 
Anyway, I have never approached the subject with my wife. I think deep
down I just didn't want to know the truth but last night she went out
again and I decided to check on her. 
I decided I was going to hide behind my car which would give me a view
of the whole street so I could see which car she gets out of. 
It was whilst crouched behind my car that I noticed rust around my rear
wheel arch. 

My dilemma is: 
Should I take it into a garage or should I buy some stuff from Halfords
and try to repair it myself?