Do it in this order:

1. Preliminary financial status & loan application checking
2. Identify property, pay 2% booking fees.
3. Then, apply for mortgage to multiple bankers immediately. If done #1 properly, it would be very easy and straightforward.
4. By 2-3 weeks time you should have it sorted out.
5. Then only you sign Loan Offer Letter,
6. Then only you immediately follow that up with signing SPA.

Do not sign SPA first before signing Loan Offer Letter!
And you can't apply for loan without paying deposit first, as banks will require a copy of the booking form for application.

Hope this helps.

PM if need more clarification.