Nothing to visit
There is no shop, no desk and no appointment behind this work. A certified translation in Southampton for Ethiopia moves as files: a scan goes out, pages come back, and a signature travels with them. That shape is why a deadline here is a question of post and working days rather than of whether somewhere is open on a Saturday.
The one address with a door
Southampton Register Office at 6a Bugle Street, Southampton SO14 2AJ is the exception. It holds the city's civil records and issues certified copies of them over its counter. It translates nothing and signs for nobody else's translation. If your paper is a birth, marriage or death record, that address is where the errand really begins.
Amharic, and who signs for it
A certified translation into Amharic is required for documents used in Ethiopia, so the language is fixed by the destination and not by the kind of paper. The credential is an ITI/CIOL-qualified certified translator, and the finished work carries that translator's signed statement of accuracy. Sworn status, which some countries insist on, is not part of the picture here.
Rate and clock
Work is about £25 / page, so the number of sheets you send decides the invoice more than anything else does. Standard delivery takes 2–3 business days and the express option comes back within 24 hours. Both are counted in working days, and neither covers whatever time the register office needs to issue your copy.