OP
Geordie Spark
If the molar is shot and must have root canal treatment to stop the pain then there is little point in spending ÂŁ300 on root treatment and ÂŁ400 on a crown when the tooth has no structural integrity.
You could have the root canal work done and leave it for a while; at least it would not hurt (afterwards), but may be unsuitable for biting on.
You could have a direct extraction and be done with the lot, the large gap is something many people have to manage, it is a nuisance but not insurmountable and you would likely learn quickly how to manage the gap.
I do not like extractions so I went for the root canal, but I should probably have "bitten" the bullet and had the extraction.
See what your dentist advises and weigh up the cost vs the inconvenience.
The cynic in me suggests the dentist will advise whatever is best for his wallet.