I put new plug leads on today and tested my fuel pump pressure. I thought perhaps the fuel pump was producing too much pressure for some reason and was overcoming the needle and seat.
I ordered a new condenser but it still hasn't arrived yet unfortunately.
Does the quality and regularity of the spark look normal in these videos? The ground on the exhaust manifold may not have been perfect as there is the standard rust/corrosion type surface on the manifold which may not have been perfect. I'm a bit unsure whether to go down the carburettor or electrical route now.
Thanks again for everyone who has helped me so far!
https://www.youtube.com/watch?v=TpBbrjg3dvg
https://www.youtube.com/watch?v=Q-0a9ERYF_c
https://www.youtube.com/watch?v=QAJw7pIhvTU
https://www.youtube.com/watch?v=iq8r8NXFoIU
https://www.youtube.com/watch?v=-dyaCogSbas