Leave old debt outstanding?

I've just looked at my credit file on Noddle and notice the only negative thing on there is a debt of just over £5k to Arrow Global. I think this is for an old credit card debt, which I haven't paid for a number of years.

The Noddle report says 'account in default' from Oct 2010. I've had no correspondence from anyone relating to this debt since at least the start of 2012 (maybe longer than that, that's as far as my definite memory goes back).

As they've made no attempt to contact me and I've made no payment at all in god knows how long, should I just leave it as it is?

I'm just covering all my bill payments every month and could do without waking a beast but I'm unsure as to how long would be left for it to be stature barred? Would it be from when it went into default in 2010? From what Noddle shows, no payment has been made since then.