OK I can help you with this returning expat stuff as I did it a year ago.
If you have not paid any income tax, council tax etc you will initially NOT qualify for housing benefit straight away (yes I know how do the people get it from other countries straight away is a mystery to me and lots of other people). What they are looking for is what is called a "local connection" e.g. you have paid into the 'system" over the past tax year. However the decision to whether you get any assistance does vary for council to council, as my home town of Bournemouth where I lived refused me and I had a 6-8 week battle with them and the job center, trying to prove that I am local (was born here and grew up here), what ever that means, as I have had different definitions from the local council, housing associations and job centers etc. There is a BIG BUT to this and that the councils have been told by government to enforce the 'local connection rule" to all applicants - Most of the onus is on you to prove you are local e.g. paid tax or council tax, you will have lots of battles along the way to get what is owed to you. I have been there done that and in fact it made me homeless for 30 day out of 45 you will have to read my blog at
http://mchphoto2011.wordpress.com to see what you are up against.
To help you get on to the system faster, get a part time job with an agency, as this acts a proof you are a local person - but you will need a pay slip or two with some form of contract. It helped me.
If you are coming to the UK without a job, then expect to pay 6 months rent plus deposit up front BEFORE you move in to any place, if you have a job you may get away with the normal 1 month rent in advance and deposit. Note different agencies do different things so ask and a lot of them do not like housing benefits customers. However as it is winter consider a long term let in a hotel, my home town a few of them do this and with a bit of persuasion you might be able to get away with 1 weeks rent and 1 week deposit and locally they run around £125-150 per week.
Also being out of the country for 5 years - you may not have a credit rating as this is taken into account as some agencies do a search on the credit reference agencies to prove who you are and do not have debts, exactly what they look for again is up to the individual agency. If you need a basic bank account most banks allow them, so does the post office.
However on the medical front, if you need urgent medical help, you can register with a doctor straight away and see a doctor - and get the med's you need on prescription. However you will not be eligible until the local connection thing comes through for operations unless it's a medical emergency, but say a routine knee op will not kick in for some time until you get that local connection. As type 2 diabetic you can get an exemption form from the doctor, fill this in and meds are free, again ask the doctor for details.
Hope this helps, as I have been through the system and survived, email me any questions you might have
regards
Michael
