I'd consider trying the Hawke Vantage 4-12x40 AO which has the mildot recticle you want.
It's not much more than 70 quid and is probably fine.
If you want to pay more there'll be a Panorama version, but I think the Vantage range are pretty good.
I like the Panamax scopes but most of them seem to have 50mm objectives.