Outdoors, certainly in a rural area, I think you just have to live with them and consider other pests likely do more damage in the long run. They are probably our commonest British mammal and each female raises about 20 plus annually with a long breeding season. That means I probably have several hundred at any given time in one acre. Voles are key to UK raptor survival and even if only tawny owls frequent your area, a few tall fence stakes which cost a couple of quid, strategically placed near raised beds will help – if there are no other tree perches nearby .
Here I see buzzards etc perching above the entrances to vole runs under our plastic mulch. Indeed from that we habituated the buzzard to come for a scrap of meat every afternoon! Owl boxes and/or tree cover planting are ideal but maybe not realistic.
I cover all empty raised beds in winter as we are in an area of very high rainfall. Agree with previous posters, voles love no-dig and they love any kind of hiding cover – indeed a snow blanketed winter helps their population peak enormously. I tried non-grass paths between raised beds but the only difference that made was I could not see their habitual runs.
We can only manage them and the more destructive field mice in the polytunnel with mousetraps and a metal quarter inch mesh perimeter barrier. Our PT is a zero tolerance zone for any rodents. but, even then, if open doorways are un-netted they will find their way in- to them it’s their local deli on their nightly shopping run. So a feral cat/cat would work well inside.
Basically, I live with them, they are mainly grass eaters and that’s key. I temporarily protect the young heads of some of my “slow ” veg such as cabbages, kales until they get going etc as the leading shoot gets eaten off but again, this is probably mice. ( A mesh ” cup”again, milk bottle halves encourage grey moulded shoots- but I will try some kind of DIY chilli spray next year. ) Also ensure there is no mulch/membrane close to the trunk of fruit trees as they provide a hiding place for bark chewing. I left a wodge of cardboard down for a week in preparation for a new bed and lifted it yesterday to find a vole underneath and all it’s eaten grass channels.
In my experience, here, mice, and of course slugs do more damage. So it’s a case of picking your battles. On balance they have brought in a whole range of wildlife to my plot and so make growing more interesting.