BMW 525i Automatic Year 2000 Mileage 110K

Smoke arising from Bonnet after a drive
Noticed after a long drive,upon parking some smoke arising from the bonnet
closer to offside window.
On inspection under the bonnet no evidence of fire or burn found. Slight
scrid smell however was present.
This did not happen for another 3 months. But some smoke was seen when I
was on reverse on the driveway.
I cannot see where the smoke originated.