Thank you all so much for your suggestions. I will investigate them all.
It is interesting that none of you advise buying the parts and replacing them, so obviously just better to replace the whole thing.
Where is the best place to buy these replacement carbs in the UK?

I am a new member ... what a great site, hello to everyone. I bought my '98 Suzuki Samurai in South Africa 10 years ago - I had decided to travel for a year - that year turned into 10, and I am now living and working in Zambia, still with my beloved Suzuki (the only red car in the village)! I wonder...