Hi,
Since they want to acquire us, I would not focus too much on the synergies, because this matters to them of course but not so much to us. Also I would not focus too much on the methodology to establish the value of the company (this is more of banker job), but on the criteria to make the decisionBelow my recommanded approach

1. Are we willing to sell ?

• How do the price they are offering compare to our valuation of our company ?
• Are we willing to sell our company in any case ?
• What will happen to staff when the company is sold (management, workforce) ?

2. Is there a threat if we don't sell ?

• What will they do if say no ?
• If they acquire another competitor and form a larger company is is a threat for us ?

3. Can we respond to the threat ?

• pro-actively looking for partnership / other acquisition on our side
• Launch lobying action to slow down their progression
• any other action to secure our business (improve offer, secure customers, etc.)

Hope this helps
Best

Benjamin