All may well until you come to sell the property. Buyers solicitors always require proper certification of any electrical work and (particularly) and work that requires notification. ie new circuits, new consumer units and electrical work in certain areas (bathrooms etc).
They will want to see that the work has been correctly notified to the local authority.
Thats where you will come under the scrutiny of an official body, and the law (notification of some electrical work is as much a legal requirement, as installing a gas boiler).
There are rumours of a purchaser being able to buy some sort of insurance indemnity policy in cases where installation work has not been properly documented, but I'd run away from a house where the vendor had such a cavalier attitude.
Now, I'm going to declare an interest here. To be a trained electrician and to carry out, and notify works I went to night school for three years while trying to keep another job going, underwent further training for design and testing, I pay hundreds of pounds a year to a competent persons scheme as well as having to keep some very expensive equipment calibrated and certified as such.
I have no truck with DIYers who want to find wrangles round the correct way to do things.