My Router getting strange IP addresses

[#1]

I've just looked at my router logs (I'm on PN Fibre) and something odd seems to have happened in the early hours of this morning.  The Router was disconnecting and reconnecting with IP addresses not only other than my usual static address, but also outside of the usual PN range.  Can anyone shed any light on this?
[Internet disconnected] Wednesday, May 23,2012 01:54:35
[Internet connected] IP address: 172.16.119.153, Wednesday, May 23,2012 01:44:32
[Internet disconnected] Wednesday, May 23,2012 01:35:53
[Internet connected] IP address: 172.16.118.132, Wednesday, May 23,2012 01:25:34
[Internet disconnected] Wednesday, May 23,2012 01:18:33
[Internet connected] IP address: 172.16.116.44, Wednesday, May 23,2012 01:08:07
[Internet disconnected] Wednesday, May 23,2012 01:03:05
[Internet connected] IP address: 172.16.119.81, Wednesday, May 23,2012 00:52:38
[Internet disconnected] Wednesday, May 23,2012 00:49:34
[Internet connected] IP address: 172.16.118.112, Wednesday, May 23,2012 00:39:30
[Internet disconnected] Wednesday, May 23,2012 00:18:28
[Internet connected] IP address: 172.16.118.130, Wednesday, May 23,2012 00:07:55

[#2]

Ah, found the answer here:
http://community.plus.net/forum/index.php/topic,79437.0.html
Although come to think of it  this is an old thread (2009). 
Is this just a one-off or is it the beginning of a beautiful friendship with BT IP addresses and an unusable connection?

[#3]

Are you on Fibre and using a Netgear router by any chance?
Try updating the DNS addresses in the router to 212.159.6.9 and 212.159.6.10 and it should fix it, detailed explanation available in this thread: http://community.plus.net/forum/index.php/topic,104794.msg893019.html

[#4]

If it's for a couple hours overnight like yours seems to be, it's usually BT maintenance either at the exchange or deeper, particularly this.
Our FTTC BB was also down for a similar period of time this morning (although I wasn't awake at the time):

Alex

[#5]

Yes I've been on fttc for some months now, and with a netgear router.  I usually put custom dns servers in, but this time I hadn't got round to it.  Have set them custom now though.l
Thanks all.