BLUE PETER presenter Tim Vincent is expected to be on the banks of the Mersey this morning, opening new attractions at the Catalyst industrial theme park on Mersey Road, Widnes, Cheshire (051-420 1121). Catalyst opens 10am-5pm except Mondays and has a range of hands-on exhibits. Admission is pounds 3 for adults, pounds 2.25 for children; a family ticket (two adults and two children) costs pounds 8.75.