Would it be worth me retaking D1?

I did AS Maths last year, which meant doing C1, C2 and D1. In C1 and C2 I got very good A grades but in D1 I didn't quite get an A (I got 74/100 which is a B). The reason I missed an A was because one question caused me to panic a bit and that affected a couple of later questions, and unfortunately the grade boundaries were quite high (it was MEI D1 - June '09). I'm thinking of retaking it (to get an A) but I'm not really sure if I want to go through Prim, Kruskal and Dijkstra's algorithms all over again, but doing Further Maths so far has made me more confident in applying maths in general and I might not find the retake so difficult.

I know that 74% is very good for an exam and I'm not desperate for extra UMS, but would it still be a good idea to redo it in case it gets entered for Further Maths and brings my mark down slightly?

It depends on what other modules you are taking this year! It seems that you are doing A2 Maths and the whole Further Maths A-level this year which is 9 modules already...adding another 1 won't make it any better so I would probably leave it and concentrate on the new modules you are learning now!