admin is right to say medical care is freely avaiable if here on a spouse visa.
But from what i have read elsewhere on a fiance visa or vistor visa its a little bit more hazey. I have seen people recomended purchasing travel insurance from the visa holders home country just to be on the safe side.
Hospitals are said to be getting tougher on health tourists, and those not deemed eliglbe in the eyes of the law.
If you can afford it i would defintely consider investigating travcel insurance for the six months just in case.
The example iwas given was you would most likely get emgency treatment but if aftercare was needed ie a bed and medical treatment you are likely to get charged if they realise they can.
others have got away with it but i would check locally to find your local health authorites policy regarding the matter.