Green, when you get stress cracks like that in a deck, it usually means (as Scurvy says) that the rig was overtightened for a long period--OR--that water got into the deck core, which then rotted, allowing the rig to compress it and crack it.
There's quite a variation in the competence of surveyors, he shouldn't have missed it and he should note in the survey about any moisture problem in the deck, or that the cracks are to this point only cosmetic. If they are, yes, you can seal the cracks and reset the rig tension (you'll need to buy a Loos Tension Guage for this, you check them routinely) and not worry. If the deck core has been water damaged, the repair is more extensive. You'll find plenty of discussion about deck repairs with a web search.
The Vega is quite a famous boat, well built to Scandanavia standards. At this point possibly a great deal but like any old boat, it can have maintenance issues. The original engines may be worn out, and spares (like the Volvo starter-alternator unit on some models) are no longer to be found. But if the boat gets a clean survey, it can take you anywhere, once you have the skills to take it.
Water leaks are not just a nuisance, they can eat a boat from the inside--structurally. So do attend to them.
One of the best ways to find all the leaks, is to seal the cabin up with cardboard and wide tape, then use a leaf blower or shopvac exhaust hose to pressurize the cabin. Honest.
Then you throw soapy water all over the deck (slippery!) and wait to see where the boat starts bubbling. And it will blow bubbles, from anyplace that there is a leak. Mark 'em all, fix 'em all, and you'll have a dry boat. (Which is a great pleasure!)