help with adddresse please

I was in England this summer. I stayed wiht very nice host family. and now i wanna send them a letter.
but i dont know how to write english addresse right. what to write at first and so on. thjere are some numbers i dont know what to do with.

please, if there is someone who could help me with it, PM or or just answer here

thank you Elanor

 

this is an example of a UK address:

56 barcombe avenue --> house number and street name
streatham common --> area
london SW16 8YY --> city and postcode
england --> country!

 

Or if they live in a small town with no area division:

28 Something Avenue (Road and house number)
Castleford (Town or city)
West Yorkshire (County)
WF8 4WE (Postcode)
England (Country)



(Edited because I'm certain the postcode comes last :&)
(Edited again after Domino's post )

 

The postcode comes after county but before country.

 

I am silly, i dont understand well.
I have the addresee - ( part which i dont understand to ) St Leonards On Sea, TN 38 ONU , what should i do with this?

thank you all guys for help

 

ok...

st leonards on sea
TN38 ONU

but the numbers are a telephone number, they arent included in the address.

 

Thank you very much, i had it on ID card, ya know. But it doesnt chnage the fact how stupid i am

 

its ok, it doesnt make you stupid, it just makesmore sense to us lot. but hey, hope they get the letter ok.