Per level at £7.50 is that plus VAT?
Is it really worth getting out of the van especially if there are only 2 levels and one black?
I understand you want to be competitive and get the work. I am all for that go in as low as you can to get the work but make sure you earn out of it.
Firstly:
how many people in the block?
How regular would it be? - they do vary considerably
Consider location ease of access
On a ball park figure as the blocks vary, and the number of people in them and the level of soiling can be either very easy and light or it can be dreadful. On average companies charge their tenants about £150 or more +vat if they are a private tenant. If they are a council tenant or housing association they get charged a smaller amount £100+vat per year. this is already be in there service charge per tenant.
I hope this helps
Dave