Spider i.d. please

[bbr]

The spider was about 1.5cm in length with a brown head and legs but had a bright yellow (almost flourescent) abdomen. The legs were thin and not overly long.

I would say the abdomen was about the size of a peppercorn and also, when looking really close as nearly invisible, you can see three sets of lines going down the back made up of black/brown dots.

It was crawling on my lavender bush.

[frits_b]

Google "Enoplognatha ovata", that might your spider. If it looks like it, it's either Enoplognatha ovata or E. latimana. Those cannot be distinguished without a microscope.
Enoplognatha live on lower vegetation typically.