Anyone know how much this would cost- changing garage doors etc

[bobthebuilders]

We've a double garage but it has 2 separate single doors and a central pillar between them. Neither of our cars will go in (I've got a VW golf so not especially big.) We're thinking of having the central pillar removed and a large door fitted but we might need the roof reinforcing to take the weight when the pillar is removed- I don't know.
Anyone know the cost? We don't want to to do this really but parking and an issue with neighbours might force us to (we have a shared drive and the other houses have double garages with no central pillar.)

[bobthebuilders]

Just to add- it is a double garage - it's not 2 singles joined together! Once you are past the central pillar which is 3 bricks across, it opens into a double.