If you have put in a visa/stay application at the home office (within the UK) and then moved address, or have/want to change your legal representative and their address, FEAR NOT!
The UK government and immigration services seem to be improving technologically these days. You can now apply for a “change your address or your legal representative’s details” via theUK Gov website.
What you should and shouldn’t use this form for is all on the page, read properly to ensure this is right for you. For example, this form is for:
You cannot use it “If you have given notice of intent to marry and want to submit a change of address” – an email is provided to use in this respect.
Additional information will needed to complete form, anyone filling this form for you need to be legally recognised with written proof of your consent to complete form on your behalf.
If you would rather send by post (personally email is quicker/better) – the address has been made available. Follow the link to get full info.