I�ll try not to bore Norman too much (I assume it�s me he�s referring to when he speaks of �our resident know-all�). However, I will try to answer your question.
If you are convicted of careless driving you will either received penalty points (minimum 6, maximum 9) or you will be disqualified for the offence. If you are disqualified, you cannot drive at all for the period of the disqualification, but when that period ends you may resume driving as before. You will have an endorsement on your licence (which you must declare to your insurers) but no points.
If you receive points, you can continue driving. However, being �new driver� your licence will be revoked and you will revert to provisional status. The points you receive will remain on your licence (they only revert to zero when you are disqualified under the �totting up� rules.
The penalty you receive will not be affected by entering your guilty plea by post, but be sure that you do enter a plea and so qualify for a one third discount on your fine.