Translating a scientific paper from American to British

Most of the differences in technical writing are spellings. Wikipedia has an article with plenty of examples. Common ones are endings: -re instead of -er, -our instead of -or and -ise instead of -ize (though the latter is accepted by some authorities in British English. There are plenty of others. Whole words include sulphur and aluminium in some contexts - in others the spellings chosen by IUPAC (chemistry) are used whatever flavour of English is used. -ae- and -oe- are much more common in British English, a simple -e- is used in American (many words in a medical context, for example)

The other differences tend to be:

• more idiomatic and therefore less suitable for technical writing than alternative phrasing.
• widely understood, to the point that whether they're Americanisms or not is a matter for debate.
• variable between style guides anyway.

A few specific cases are worth mentioning (addressed from the point of view of academic British English):

• gotten isn't a word.
• spelt is the past tense of spell and not just a form of wheat (spelled is also acceptable).
• British English is more likely to double a final consonant when adding a suffix.
• we fly in aeroplanes not airplanes.