Rangemaster Electric Oven not reaching heat?

Rangemaster Toledo 110 Dual Fuel - left hand conventional oven not reaching heat. Bottom element working fine. Top element had been damaged & not heating fully so replaced with new one. New element heats up slightly but not fully so oven does not reach temperature. Re-checked connecting wires which are all in place. Any ideas as to the problem / solution ?

Daren
October 2012