Rover P3 75

We bought our P3 as a largely restored runner that we could use whilst finishing off the projects that previous owners had not completed, such as interior trim. We'd done some research into the history of the P2 and P3 and knew that we wanted this particular body styling, which we found very appealing. We also needed the interior size as both my wife and I are tall - we'd tried fitting into a Morris 8, but we were too big! The Rovers are much more spacious - ideal for long backs and legs. This is essentially my first classic car, but I was back on familiar ground as I'd owned a 1950 built series 1 Land Rover (80 inch) when I was 17 - my second car - so there was quite a bit in the engine compartment that brought back memories of the early Land Rover. This particular car originated in Berkshire (coincidentally, just as the Land Rover had done) and was brought to Cornwall many years ago, where it has remained. The only problem I've encountered is a tendency for the engine to misfire and lose power when warm and climbing. It starts well and is a powerful runner, but this loss of power when warm might be indicative of tuning or it's in need of a more modern carburettor system. I understand from reading club magazines that this can be a common problem with various remedies providing the answer. Like all diagnostics, it's going to be a process of elimination. All suggestions welcome. The photographs show the car shortly after purchase from a private owner in Autumn '07. The original driver's and passenger front seats are removed and in need of re-upholstery. The cloth substitutes are for the time being comfy and practical though obviously not original. The rear light lenses are originally from a Morris Minor. Everything else appears to be original. We'd be very interested to know just how last-of-the-line this particular car was, being built in 1949 just before the switch to the P4.