You would expect professionals to be properly qualified. Doctors, dentists, solicitors, electricians, driving instructors and so on are. Amazingly, in the UK accountants may not be; anyone can set themselves up as an accountant. Indeed, it is not unusual for trainees who failed to complete their qualification to set up independent practices as no one else would employ them.
A proper qualification is far more than evidence that the accountant passed exams as some stage in their past. It shows the accountant has kept their knowledge up to date. They will have demonstrated the highest professional standards. They must comply with best practices and professional standards. If something does go wrong, there will be a complaints procedure.
Above all, a qualified accountant may well be no more expense than an unqualified accountant.
HM Revenue and Customs require the taxpayer to take due care in preparing their accounts and tax returns. Engaging a properly qualified accountant will normally meet this requirement. With an unqualified accountant there is no such assurance.
In conclusion: make sure your accountant is qualified and has a current practicing certificate.