Think the government are getting it wrong on this one. People found innocent should be entitled to full legal costs back. If this costs the government too much money, then this risk should be considered in the CPS's calculus on whether to prosecute the case in the first place.
Yes this increases the risk a guilty person will escape the justice they deserve (and this might harm innocent people indirectly) but a fundamental hard constraint of our justice system should be that its direct actions do not harm innocent people.
If successfully proving your innocence can put you in serious financial difficulty, then the authorities can punish people by simply bringing the case, rather than having to actually prove anything.
