Unfortunately there is a national shortage of radiotherapy treatment machines (and also a shortage of the staff to operate and maintain the equipment) so long waiting times for treatment are common. The government is spending a lot of money to change this but it will still be some years before the situation really improves. This is because it takes many months to install new radiotherapy machines and 3-4 years to train staff to operate them .
This means that it might well prove difficult to find a hospital in another area where you could get treatment done faster. Even if you did find another hospital your own doctors would have to make arrangements for you to be referred to the specialists at the other hospital . They would then want to reassess your case before starting the treatment. By the time all this was done most of the eight weeks would probably have passed and you would have gained relatively little but would have the inconvenience of a lot of travelling for your treatment.
It is also the case that usually Health Authorities would be very unwilling to pay for treatment outside your area if that treatment can be provided by a local hospital (even if there is a waiting list).
Having said this all radiotherapy departments do look very carefully at the urgency of the need for treatment for every patient. Although it is often hard for patients and their relatives to understand, or come to terms with, very often radiotherapy for cancer (particularly if it is being given as a precautionary treatment after an operation has removed a cancer) is not very urgent and a delay of even a few months does not reduce the chance of cure.
Usually if the doctors feel that radiotherapy treatment is needed urgently then those patients will be given priority and get treatment more quickly (although this may still mean a few weeks wait).
Almost certainly the hospital where you are to be treated will have looked at your case and decided that a wait of eight weeks will not reduce your chance of successful treatment even though they and you would much prefer to get it done sooner.

