Yeah a bit daunting at first, but just take your time, keep hands really clean, the pillar trims can just be partly pulled off at tops and bent down just a little. The worst bit was removing the old FM connector working upside down, a mirror would of helped. In the end I just yanked on it with a pair of pliers. You need a 20mm spanner and someone to hold new aerial in place whilst you fight to fit the nut underneath upside down. I ran new cable down passenger A pillar and above glove box, as I had been that route before with window aerial. Don't worry about airbag in A pillar, just leave it well alone ;O)
Oh just to make sure, you have got the DAB button on front top rh of rcd510? otherwise it won't be a DAB unit.......