As far as the criminal damage goes there is only one witness - your neighbour. You can provide no evidence to support the allegation. However, the uncooberated evidence of a single witness if often sufficient to secure a conviction.
The problem you will face is that the police will probably deal with this (if they decide to deal with it at all) by way of an "out of court" disposal (i.e. a caution or conditional caution). This will depend of the seriousness of the offence and the alleged offenders previous record, but if the damage is slight and/or the offender has little or no "previous" a caution may well be the outcome.