Rules and regulations for residency?

British citizens can enter Bulgaria without a visa and stay for a period up to 3 months. If you intend to stay for longer than 3 months, you will need to apply for a long-term residence permit from the Migration Directorate of the Bulgarian Ministry of Interior.

British nationals who have resided legally in Bulgaria for a period of five years on the basis of a consecutive long-term residence permit are entitled to a permanent residence permit.

Step-by-step guidance in English on obtaining long-term and permanent residence permits is available on the Bulgarian Ministry of Interior’s Migration Directorate’s website.

For further information contact your local Migration office or call +359 (2) 982 4808, email: migration@mvr.bg.

So OK I could possibly come and go under the radar kind of wondered on that one and in fairness the Bulgarian language test too, I have only visited on shorter trips throughout the past 4 years so a longer stay would be an advantage regarding restoration and DIY work for the house, (near Byala Ruse).
I was not sure if my passport would be stamped if driving through?
Regarding the legal way on three month terms and applying for further stay this is what I had assumed from various forum posts, but again needed some more clarity.
In layman's term's I could rock up in say February and stay until April/May without any permit's, but also I could then re-enter I suppose without little opposition, and stay again 3 months or whatever?
OK it is something I can consider and plan towards.
Thank you for your help and advice.
Steve.

Looking at the website the layout seem's quite straight forward, unsure as everyone is on the EU situation currently still in the UK and EU so it is a matter of time to see how that pans out?
Thank you though for the links, I have something to relate to now regarding legality?
Regards Steve.

I'd be careful about overstaying your allotted time. Getting a resident permit is so easy for EU nationals. I think it is something like 10 lev, and another 45-90 if you want an ID card. And I thought that you could immediately get a permanent instead of a long term, which is good for 5 years.

Although it is rare to get cited, you can get a fine if you are caught overstaying without registering- usually when your passport is checked on the way out, so why risk it?

I believe the amount you can stay without registering is 90 days every 180, so you could come, stay for 90 and then you have to leave for 90 before reentering, or you can stay for 30, leave for a few days, come back for 30 more etc. But definitely check the portal.

But just... please, follow the rules people.