Martin Williams opened the scoring with a low angled shot after 24 minutes, and two minutes later Andy Lomas saved well to deny him another.
Mick Swaysland, Malcolm Ndekwe and Kenrick Roudette all went close, but in stoppage time Bowen struck to make it 2-0.
On 51 minutes Freeman scored a third, and on 57 minutes a superb Lovell header ended the contest.
The second goal proved to be a killer blow to United, and in the second half they rarely looked like repeating their Cup Final win over the same opposition at the end of the previous season.