I got my ED visa from UK. Although the online system is a pain, as you have to compress all files very small, I'd highly recommend doing it by post. You submit your docs online, then send originals by post with £10, then they post it back. Mine was returned in 4 days and no appointment required. Make sure you meet all the requirements and submit all the required documents. If you're not sure what something is, email them for confirmation so you're really prepared. I got a reply the same day with clarification. Your school should provide you with a lot of documentation to submit if they're a legit school. A tip for the online submission if you go that route, if a doc has more than 1 page, they need to be in 1 file, not separate files. Then compress the file so it meets the size requirements.

Out of interest, did you have many stamps in your passport? And was this your 1st or 2nd Ed visa.

I've friends planning to go there so thought I'd pass on the info :) TIA

Oh and the letter is super important. My visa was cancelled in my passport but they still wanted the letter.

They prepared a letter for me that confirmed I was no longer working for them and the cancellation. They gave me this to me the day the visa was cancelled and I left within 24 hours. I understood I had to leave within 24 hours. At the border they spent about 15 mins looking at the letter and confirming it was real. Then I was stamped out and came back in 15 mins later on a visa exempt entry. Ask Mam and T. Waew what they did for me. They have done it before and know the process. Agree a cancellation date and book your bus now so you're ready to go as soon as you have the letter. I got mine around 3pm and left at 8am the next morning.