12 examples of changes in modern British English according Micheal Swan "Practical English Usage".

1. Will and would have now practically replaced first-person shall and should.
"I would be grateful for some help."
"The will be in touch soon."

2. Subjunctive "were" is becoming less common.
"If I was ten years younger I'd do the job myself."
"I wish it was Friday."

3. The common American use of a past tense with just and already is also becoming common in British English.
"Daniel just went out."(instead of Daniel has just gone out.)
"I already told Megan about the party."

4. May have is increasingly used (like might have) for unrealised.
"Better treatment may have kept woman (who died) alive."

5. Stood and sat are now frequently used in standard English for standing and sitting.
"We found Smith sat in a corner reading a newspaper."

6. Be like is now very common in spoken English as a way of introducing direct speech.
"She was like, 'What are you doing here?'"

7. Who is replacing whom.
"Who do you trust?" (George Bush's 1992 election slogan)

8. Some adverbs without -ly are becoming more common.
"You pronounced it wrong."

9. Comparatives and superlatives with more and most are two-syllable adjectives.
'Commoner' used to be commoner, but more common' is now more common.

10. Plural noun modifiers are becoming more common.
For example, "antiques shop" is now as common as "antique shop", and "drugs problem" is replacing "drug problem".

11. The (very old) use of less with plurals is becoming more respectable.
"There were less people than I expected."

12. Some American English prepositional uses and phrasal verb forms are moving into British English.

"The following trains will not run due to engineering work on weekends." (instead of... at weekends.)

We met with the unions yesterday. (instead of We met the unions...)

"Can I speak with Cathy?" (instead of ... speak to...)

"We haven't seen Granny in ages." (instead of...for ages.)

"You have to fill out this form." (instead of ... fill in...)