In reply to SandstoneYorkie22:
From what you have described so far a 50 metre rope should fit the bill. Very few trad rock climbing routes in the UK need a longer rope. A single rope should be fine for many alpine classic routes. A triple rated rope may give more flexibility for the future - you could pair it with another rope for more technical routes if required - but also tend to be more expensive, less hard wearing and thinner to handle which may not be ideal for you. You may not need dry treated at this stage which will save you some money, but if spending time on snow and ice on the alpine routes you choose then dry treated would be worth it.
There are often great rope deals. Look out for Decathlon, Bananafingers, Go Outdoors, Dick's. I'm sure some others will reply soon with good sources for suitable ropes...