To be fair to LCM, the ERIC system has only just been rolled out, and with any new system you can expect glitches. Hopefully they'll learn from these for the next exam session.
Like Sbhoa, my local rep is fantastic. She is able to request a specific week to hold exams and most of the time she will get the week she asks for. If not, it is usually the following week. In over 5 years, I haven't known them to be earlier. With the ERIC system, she is notified of the dates of the exams at her centre and is given a list of candidates. It is then up to her to slot them into times. So if I have a candidate who can only do early mornings for example, I can request that. This flexibility is what makes me prefer LCM over ABRSM. The actual notification is usually around 14 days before the exam, but when you know which week it's going to be it helps a lot.
The slow issue of certificates annoys me too.