The English army is stronger than ever the next time you see it from your advanced position on Telham hill. They mass more deeply and take up even more of the opposite ground than they did before: reinforcements have obviously joined the king in the intervening time. Your army is weaker than it was.
Persist anyway, by tossing that annoying coin: heads you win the battle: tails you lose. Heads twice and you killed Harold: heads three times and you killed his brothers too: tails twice and you are dead. If you tossed heads three times, then you managed to pull it all off after all. If you lost the battle (but survived) you accepted terms and withdrew to Normandy in defeat. If you won the battle but didn't kill all of the Godwinsons, then you still haven't won anything. Try again? Toss that coin just like before: three tosses of heads will kill off the Godwinson survivors; two tails will kill you; one tails will lose the battle and you go home. If you haven't won or died by now, you have to go home anyway, unsatisfied. No more chances for you to raise another army for a second go. History knows you as William the (persistent) Bastard. (It could always be worse.)