I recently read an article published by the West Sussex County Times on salaries for specific jobs and would dispute the majority of the accuracy in the article.
The majority of administrative roles in West Sussex pay £18-20k and not £25k, which is more like London salary for this type of vacancy.
Even then, I have recently been sent administrative support roles in Central London at £22k, so not sure where you are getting your information from.
Administrative support roles are classed as an overhead in the majority of companies and the salaries have not increased within the past ten years.
See examples below from various online job boards for the Horsham/Crawley area.
Businesses in this area repeatedly bemoan the lack of recruits with the relevant skills, but if you are paying wages below the expectation of a highly skilled and experienced employee, then it is not surprising they struggle to fill these positions.
I refuse to work in both Horsham and Crawley areas, as the pay is poor, commute is lengthy, traffic appalling and parking very expensive.
Examples from online jobs boards:
Financial Planning Administrator, Horsham, West Sussex, RH12,£20,000 per annum
Customer Service Advisor, Horsham, West Sussex, £19,000 per annum
Recruitment & Training Administrator, Horsham, West Sussex, £18,445 per annum
Administrator, Crawley, West Sussex, £18,000 to £20,000
Pensions Administrator, Crawley, West Sussex, £19,000 per annum.
Turners Hill, Crawley