When you run the compression test, make sure the engine has reached operating temperature. While you take the measurements you have to hold the throttle wide open and crank until the reading no longer increases.
The target is to have (hopefully) all the values within about 10% of each other. It's not that there's a specific target number to aim for. In your case, you could make the argument that an "average" number was 105 psi and therefore, both your high and low numbers were almost within 10% of the average. Your numbers may be a little low, but BL/Rover did make some low compression engines so I can't say if your number are "too low".
You and your boyfriend may wish to invest in (or borrow) a leak down tester. (That assumes you already own or have access to an air compressor. ) You can go to eBay and search for leak down tester to see pictures of them. (In fact, I just checked and there's a guy from TN whose selling what look to be the Harbor Freight leak down testers for very low prices. ) To use a leak down tester you bring a piston to top dead center connect the tester's spark plug adapter to that cylinder. You apply 100psi air from the compressor to the tester and read its output gauge which gives you a "percent" leakage. You WILL have some leakage. While the tester is blowing air into the combustion chamber you listen around the car for where the air is escaping (out the tailpipe = exhaust valve leak, out the carbs = intake valve leak, into the radiator OR out an adjacent spark plug hole = head gasket blown, out the dipstick hole = blow by past the rings). Some air WILL go by the rings. If you see a leakage percent below 20% and it's coming out the dipstick hole, I would not worry about the rings yet.
So, did you get that radiator and pump installed yet? I wouldn't worry about the compression and its affect on temperature until you've got that installed.
BTW, did you check your ignition timing to see if it is correct? Timing can also affect the operating temperature of the engine.