In neutral does the gear lever spring back to centre if pushed left to right across the neutral gate?
Mk1 Focus has a spring at the base of the gear lever that commonly breaks so that the gear lever loses it's self-centreing action.
http://www.fordpartsuk.com/shop/ford...2069_c_100.htm
Pretty easy to fit, just remove the centre console and the lever, few screws hold the lever into the base, then a matter of fitting the spring on the lever at the base so it springs both ways.
Can see the spring at the bottom of pic, below where the finger is (Google images)