New cars will always lose a bucketful in their first few years, as you have unfortunately found.
I have just used Parkers (yes I know) to get a feel of the situation.
Lexus Is200 SE Auto 2004 on a 53 plate.....
Cost new = £21,535
P/X Value now = £15,000
Citroen C5 Exclusive V6 2004 on a 53 plate.....
Cost new = £22,477
P/X Value now = £8,080
Lexus Is200 SE Auto 1999 on a T plate...
Cost new = £23,195
P/X Value now = £8,140
Can't be all that bad in the long term ?