When you SARN a lender's agent, such as Hammond Suddards Edge, that agent is required to send you copies of everything that is held on you in electronic form (eg held on a database system). The material you have been have sent sounds unusual in that one would expect it to be held in either paper or microfilm form, thus (at present) falling outside the scope of the Act [though this will change in October this year].(posted 8399 days ago)I SARNed Eversheds, Abbey National's agent in my 'case', and was sent material which appears to be much more of the expected type: screen dumps, database printouts, electronic log entries, etc. I didn't get anything such as you describe above from Eversheds.
In my humble opinion the response to your SARN seems somewhat idiosyncratic, although it may be that Eversheds and Hammond Suddards Edge operate very differently - although I don't know why this should be. I'd ask the Information Commissioner for an assessment. In the meantime write back to H.S.E. and ask them for a full explanation of their processing and processing logic. Also ask them if there are any coded or abbreviated references to your MIG or anything else they haven't explained. This will give you some insights into their thinking.