Relearning the English language

I'm now in the UK (approximately 10,000 km away from Malaysia). When I first got here, I thought my English was of 'average' standard and Malaysia being an ex-British colony, I spoke fluent 'British' English. However, with the influence of Manglish and American sitcoms, my English is no where near 'British English'. I had a few embarrasing moments during some of my daily conversations with people here. On one occasion, I was working on a project that involved the disposal of a business producing bread. As you would expect, they had flour mills to store the main ingredient for bread making.

Me: I'm happy to look at the flour mills operation
Colleague: Can you pronounce 'flour' again?
Me: f-l-a-r. .....
Colleague: Dude, it is pronounced 'flower'
Me: What??? That is the first time I heard it pronounced that way

So I looked up the dictionary to check how it was pronounce to prove that what I was taught the right pronunciation in Malaysia was correct. This is what the dictionary showed - flouuhr, flou-er (Source: http://dictionary.reference.com/browse/flour).

Another one was 'handphone'.
Me: What is your handphone number?
Colleague: What is a 'handphone'?
Me: Mobile phones, your Nokias and Sony Ericssons.
Colleague: That must be what Malaysians called it.
Me: I guess so (*confused look)

Again with the trusty dictionary.com, I typed in 'handphone'. Result - Redirected to another website selling phones. That has never happened before. So I tried another dictionary website - thefreedictionary.com. Result - Hand phone is not available in the general English dictionary and thesaurus. Mental note, never use the word handphone again in the UK.

A few more that I can remember are:
Chips = French fries
Crisp = Potato chips
Datakey = Pendrive
Photocopy = Photostat
Stamp = Chop

I bet if I travel around Europe and even the UK, I would encounter many more varieties of English. Since my work, involves presenting my work in 'British English' I fear one day my reports will be given back to me with hundreds of question marks and scribbles asking me to explain what I'm trying to say. My writing would have a combination of British, American and Malaysian English. I've now signed up for an English course to 'relearn' my English. My company provides this training for free so hopefully, my 'English' will improve after a couple of months.

Everyday is a struggle not to use phrases that I love:
"Can ar"
"Where got"
"-lah"

-Adrian