new igo map showing old speed mph on gps??

I have recently got a 7" gps called gps 84h-3 which loads up at the starts up with mediatek. http://www.ebay.co.uk/itm/251244817086?_trksid=p2060778.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

the maps were outdated 2012 infact, but I have loaded some igo 2014 maps, but when using it again today I have noticed that certain places such as clifton boulevard in nottingham which is the a52 road where the speed limit changes from 40mph to 50mph which was changed years ago my gps is still showing 40mph on it. I have deleted the old uk maps out and replaced with new 2014 so why is this still showing 40mph? surely if the maps was not installed properly my sat nav would not be able to pick up the map right?

Also I have noticed these chinese gps's are loaded with different software such as igo,navtek etc is there anychance i can flash mine with better software? And how do i get tomtom maps to work with this gps? Any help much appreciated.

Sorry if this is posted in the wrong section of the forum?

When you say better software (than you have now), then you should first say what software you have now.
Also when you do a read on the forum, you will find that TomTom is no good choice for a WindowsCE6 device.

The speed limit that is shown is "baken" in the map. So the mapmaker did not resolve all faults, updating the map.
Changing the map to another maker can help out (locally), but it's guaranteed next you will find other faults.

I downloaded the latest igo map 2014. The 40mph to 50mph was altered 4 years or more ago so I fail to understand how 10 new updates or more this hasnt been addressed. I am not the only one in Nottingham who has one of these sat navs and the a52 is a very common road next one of the main hospitals in Nottingham. How do i find out what software this is running?

The TT for iGO maps are the best for your area - or so I'm told. Unfortunately the mapmakers do not seem to keep up with the latest changes since they're probably not in your area checking everyday. The best that can be said is to wait until the next set comes out and see if the changes were properly made.