The 2007 E63 650i is notorious for experiencing engine oil leaks.

[Craigbelont]

Yesterday, I had the oil filter replaced and was informed that there is an engine oil leak. I was already aware of this issue as it was brought to my attention by a MOT garage in November.
I have travelled a distance of 4000 miles and it has been 18 months since my last oil change. I have not added any oil during this time. When I checked the dipstick 2 weeks ago, the oil level dropped down from the maximum level to 10mm above the minimum level. It seems that there is not a significant oil leak, since there is no oil visible on the driveway. However, there have been reports of a substantial amount of oil accumulating in the bottom tray. It is possible that the leak is originating from the rear of the engine.

From where should I commence?
I have saw the video from @Timm about leaks. I am also contemplating eliminating excessive repair expenses.
The automobile has a low mileage of 56,000 km, however it is 15 years old and still has the original plastic/rubber seals with the "BMW" logo.

The closest independent BMW dealership is Birdsauto located in Iver. Although they have received positive ratings, their services are known to be expensive.

Thank you.

[Craigbelont]

Should I attempt to use Wynns Stop leak or is it already too late?

[VWDaveBMW]

Performing a thorough and meticulous cleaning is the first step to take in order to increase the likelihood of pinpointing the source of the leak. Once the origin of the leak is determined, you can then proceed to make an informed choice on the appropriate course of action.

[Screwdriver_1]

I agree with the statement above.

[Craigbelont]

Has anybody used the services of "P&R BMW specialist" located in Hayes UB3?

[VWDaveBMW]

Consider reaching out to @bwchiptune, since he is located in the same vicinity.

[Craigbelont]

I am aware.

[Craigbelont]

Update: I had the BMW dealer do an inquiry into the leaks:

1. There is a leakage of the engine from the valve covers of the cylinder head.
2. Gearbox leak: The issue involves the oil sump, adapter, and seals of the pan filter.

Their repair estimate is very high.
Can anybody provide a reference for a garage in the UB9 area? Alternatively, are there any individuals willing to be compensated for their assistance?

[BenTrevor]

Following a 5-year hiatus from the Bmw 650i community, I have just acquired another vehicle of the same model and am once again engaging in the same endeavour. I am seeing leaks originating from the valve covers, timing covers, and many additional seeping o-rings. Rectifying such issues, including a thorough cleaning, will need the effort of a whole weekend. Subsequently, it would be necessary to inspect the integrity of the alternator bracket seal. My point is that one should not anticipate a successful repair on the first attempt when dealing with leaks in these vehicles.

[Motoman]

Based on my own observation, chemicals are ineffective in preventing leaks between components that are in motion. These issues are mostly caused by an excessive amount of movement between a shaft and a bearing, or in some instances, a seal that has been hardened or fractured due to excessive movement. If oil is leaking between the gearbox and the engine, it is probable that the rearmost crankshaft bearing in the engine is the cause. Revamping engines is not really difficult, but it does need a well equipped garage.

[DreamWeaver]

I have added a few more things to the current situation