1. I can buy replacement parts. Yes
2. It won’t break immediately as I run it around. Yes
3. Is this an off road buggy? No
That body with TT-02 platform is not intended for off road, so it will struggle, if run at all, on grass. It is definitely NOT recommended if off-road capability is a critical characteristic.
I don't know about that side of the "pond", but in North America, the best resource of Tamiya parts remains Ebay. The international nature of Tamiya and Ebay makes it far easier to acquire and maintain a healthy inventory of spares.
That being said, maybe consider other chassis options, such as the XV-01 or DF-03RA. They better handle off-road, even though accommodating full fendered body options.