Vauxhall Meriva dashboard won't light up

Hi everyone, I hope someone out there can help! I have a vauxhall meriva, 62 reg. It hasn't done an awful lot of miles, but had a new battery fitted at the beginning of this year as the old one wasn't holding any charge. I took it out for a run regularly so it didn't die again on me but over the last couple of weeks wasn't able to get it out. When Icame to start it up, it wouldn't start, so we jump started it from the other car and everything went fine, except the speedo and rev dial and my little screen displaying mileage etc now wont light up ! The needles are moving when the car is driving so as long as it's daytime I can see what speed I'm doing, i just can't see a thing once it goes dark, unless I driv past a lampost and get a bit of light! Everything else is ok, headlights , radio, etc, just these displays on the dashboard....I asked an RAC man and he said he's never seen this before ! Any ideas before I take it to an auto electricans and get ripped off!!?