Yes oj, that is the statutory maximum fine if the matter is taken to court.
Most offences of no MoT are dealt with by way of a fixed penalty. The matter is usually taken to court only if the offence is committed along with other more serious matters, such as no insurance.
If it is prosecuted in court, magistrates' sentencing guidelines suggest a starting point fine of half a weeks net income (reduced by a third for a guilty plea).
Although I could not be sure, I would hazard a guess that nobody has ever been fined anything like the maximum of �1,000 and I doubt that few, if any, have been fined even half that amount.