It's what was once known as Senecio 'sunshine', now called Brachyglottis 'sunshine'. Leave it for the winter, and in spring, as growth begins, hack it back as far as you like - it'll recover and grow on again.

Thanks for the tip. It sounds a bit drastic, but I'll do that next spring.

It's up to you how far you take it back - but let's face it, it looks pretty woody and messy currently, and I'd certainly reduce it by half all over next spring.

I used to have one of these and it grew enormous. I followed the same advice that Bamboo has just outlined, but with some trepidation, and it actually benefitted mightily and gratifyingly. It was like having a new plant! I reduced mine by somewhat more than a third and it still bounced back.

I have one in my front garden which is North facing, I grew it from a cutting I took some years ago from a bush that was used as hedging. I hack it back now and again virtually to the ground to keep it small. It's thriving and always produces nice yellow flowers. I've taken some cuttings from it this year as I want to plant one in my back garden to fill a space. It should do better in a South facing position.

I'de take at least 2/3 of the plant away that's near your lawn. You could do it now, be as drastic as you want, it will come back.

Erm, I wouldn't do it now, not having seen the dreadful forecast for this coming winter... tip the tops if you like, but leave the hard prune till spring.

It looks as though I can give it a good hacking without worrying, but I think I'll wait until spring to be on the safe side. Thanks everyone.