How long have you been there saltire? When you say x number of days in the last 7 months, does that mean you've been there 7 months? In which case they might be being harsher about it, or might decide to call it a day because they feel you are a bit unreliable. Not saying this is justified, but if you've not been there long you don't have many rights at all.
You say about 1st sickness, verbal warning etc etc then up to 5th sickness written warning or a disciplinary. So are the earlier warnings not part of the formal disciplinary process then, just informal warnings? In which case that's a lot less harsh obviously, more like 'having a word.'
Lots of places do have draconian sickness absence policies, retailers often known for this.