You can probably rejuvenate. You will lose next years flowers but if it wasn't flowering anyway that's not an issue. Normal pruning to keep the bush flourishing is immediately after flowering as it flowers on the wood formed the previous year.

Rather than cut the whole thing down, I suggest you cut out about one third of the old wood to the base. Give it a heavy feed next spring and make sure it doesn't go short of water if we have a dry year. It should make lots of new growth. Cut out another third of the old wood the following autumn, and the last third the following year. The shrub will then consist of young growth, which will hopefully carry flowers.

Thanks to both of you for the advice. Cutting back today........as soon as the rain stops!!