Both low beams failed

[pysspd62]

Hi. Both my low beams have failed simultaneously yesterday - everything else electrical works - apart from slightly intermittent central locking issue. Changed the dash switch for another I had and checked the bulbs and fuses - they all seem fine. Multimeter suggests power at the bulbs and the switch turns that power on and off. So, I suspect there is an earth failure somewhere. Before I fork out for an electrician, is there anything else that can go - like a relay,for instance? If I need to get someone to look at it would people recommend a garage or an specialist electrician? Anyone else had a similar problem and what did it cost to sort, just so I have a general idea of what it is likely to cost - buying another car might be cheaper!

Thanks

Simon