Can you just deselect the RDS ?
If I remember right you tune the radio using manual setting, it works if you are in one area all the while but if you are travelling distance you will have to retune the manual setting.
Have you got the standard aerial on or a trendy but useless short one.
As Graham says check connections especially the roof mount as water tends to get in there and corroded the joint.
Are we there yet????? No we fecking ain`t gggggrrrrrrr
Ex 1.6hdi van now 3 seater 1.4 multispace
The radio should search & find stations & if you put them in the memory the rds will tune national stations like Radio2 etc wherever you are. If you are in a remote part of Wales you may be in a poor reception area, If you are driving in mountainous & remote areas reception of even the national stations can be poor. Should be ok in urban areas & main roads though.