Posted: 13/04/2016 at 14:50
The v is for veteran which as discussed above is often 35 year old and over for female and 40 years old and over for men although this isn't always the case.
Some races will split runners into several categories so if there's a V35, V45, V55, V65. In this case, you would be in the V35 if you are 35 or over but under 45. You would be in the V45 if 45 or over but under 55 and so on.
Some smaller races might only have a senior and veterans category, other events like parkrun split runners into 5 year categories.