Mish1.... Hopefully of the Beta blocker it will be OK.
However it all depends on what "degree" of Heart block you have. Ask your GP as they will need to do an ECG, before you get your answer, if it's 1st degree it's just a very short delay in the signal, it's not a problem.
Any other Heartblock will have to be investigated by a Cardiology team /Cardiologist , it's normally a fast referral and I'm sure your GP will have informed you, that's what they would do next.
Don't over worry please, it will be fine I'm sure.