The first option to investigate is going to the bank that holds the first mortgage over your personal home and see if they will advance you more funds against the house, using the 25% equity you have available. I’m not sure you will have any success moving your business lending as currently a bank is unlikely to take on distressed lending.
The reason your business bank will not entertain a guarantee from your house lending entity is they have no control over your house as the first mortgagee controls the liquidation of your house should it be required to pay off business debt.
You will be eligible for the new SME business loans which is $10k plus $1.8k per employee so make sure you get access to that asap.
I was a corporate banker for 20yrs and would be more than happy to help you in discussions with your bank, it is often just getting to talk to the right person as they are big organisations.
If you want a hand with your bank let me know and I’ll send you my contact details.