Stuart, I suspect that this will be more than drainage holes and feel that it is more likely to be a seal(s) that needs replacing on the bulkhead between engine and passenger compartment. Strongly suggest that you buy the workshop manual from Halfords. Probably £20 but well worth it.
I can answer this question...
How can I fix my Chevrolet Matiz?
Please wait ...
howtomendit.com for free repair help, information and advice.