Silly question guy's but is my standard 128 3P unleaded of does it require an additive? It always sounds a bit tappy and I have suddenly wondered if I am stupid

Well, it would have run on 4-star originally so should be on unleaded plus additive but it depends on your mileage - they recon valve seats have a "lead memory" which lasts 20,000 miles ish.

Thank you for your reply
What a donut eh!!!
And I'm glad to hear about the memory, shame about mine

Don't count to much on that "memory" story, and use a good additive, like Millers VSP, together with quality fuel, like Shell V-Power.