Buying a Polo Mk4 - query of CV boots

I've been involved in a car accident (not my fault) in my trusty Y Reg Fiat Marea and they've decided to write it off.

In the meantime, whilst I get some pennies together I've been offered a VW Polo 1.6 GL but I need some assistance and hope this is the best place?

Basically, it's got 114k miles on it, but is tidy enough apart from a few bumps and scratches but it does have a bit of rust near the driver door handle on the rear panel.

It's got the usual spec of alloys, CD player, sunroof etc and is pretty nippy for a 1.6.

My biggest problem is whilst turning the steering whilst moving and I get a knocking, perhaps about 3 knocks on a quick 90 degree turn.

I'm guessing this is the CV Boots / joints but am unsure if it severe or not.

It's someone I know who willing to sell it to me as is for £500. Any advice would be appreciated?

Many thanks