If the amount of tread left on your rear tyres is more than 4mm, it would be safe to simply replace the front tyres, otherwise replacing all four would be the safer option.

If you do decide to replace all four tyres, we would suggest looking at tyres such as the Kumho Crugen HP91 or Hankook Ventus S1 Evo 2 X, both of which have good ratings for efficiency and wet grip. Because the tyres required are relatively large even the cheapest options on blackcircles.com are around the £100 mark. As these are summer tyres rather than an all-season tyre they should last longer, but ultimately the size and weight of your vehicle will determine how long they last.