Nerfing the UKF medkits, making them the same as grenadiers, would be a better option imo.
Only the vet 1 requirement is something I don't understand, make it stock or an upgrade like the UKF. Change vet 1 into something else i.e. spread the bonuses of vet 2&3 more equally.
But brits healing does not work same as ost healing.
Brits medkits are balanced around being primary healing method, with their medics being awkward and only supplemental.
With ost, its reversed, medics being main heal, medkits being just supplemental option and you still have 251 healing on top of that all.