Ray, don't worry, you're not damaging the gearbox. What you have is just regular clutch and synchromesh wear in the gearbox. It isn't worn out. My own V40 has less than 12,000 miles and is not yet 1 year old, but sometimes first gear makes a small 'bump' when engaged. It maybe a good idea to drain the gearbox oil and fill with fresh stuff when you get it serviced, this should help.

The fuel light problem must be because the sensor in the tank is not calibrated right. The tank holds 60 litres, so do not rely on it!