It's a gamble, you may be fine but you may not be. You have to ask yourself why there's no service history. Few reasons, they may have lost the book, not kept receipts or they may just not have serviced it.
When I got mine it had little service history,
dealership services up till its first mot but nothing after that. Milage was low but confirmed by mot certificates so I took the gamble. My brother is a mechanic and does all my work so having no record of timing belt wasn't an issue as he just stuck on a new one but if I had to pay for mechanicing work I doubt I would buy one that had no record of a new one. My downside is that I don't get proper bills for work carried out so have to rely on parts receipts which I am pretty bad at keeping! Come to think of it its due a service soon (must keep receipts!).
I'm waffling again but what I'm trying to say is there can be genuine reasons (albeit not very good ones) for not keeping history. It's a difficult one, having service history is no guarantee that's there's nothing wrong with the car and does not mean it will never break down. I would go more on the condition of the car checking for usual. suspects like mayo on the oil cap or oily smelling coolant. Proof of regular oil changes is always piece of mind for these engines though given the potential for oil pick up issues if they get gunked up. My perhaps **** rule of thumb is if a car looks like it's been neglected it probably has been.
It's up to you of course, for what it's worth I would say that's a lot of miles with no service history, i would only get something with
lower miles with no history. The most important thing is what you think of it and of course the price, if it's a fair bit cheaper then that can pay for a lot of piece of mind repairs. I
One definate though is make sure the price is less than an equivalent one with service history as service history is definately worth money.