The Lenovo B50-45 has an AMD E processor family which is better than the Intel Core i5-5xxx processor family found on most portable PCs of this age and spec.
An AMD E processor family is actually the worst processor family across all laptops that were released more than a year ago.
The best processor family across similar types of notebook PC is Intel Core i7-3xxx.
Other notebook PCs that have an AMD E processor family currently available which you might also want to consider include cheaper laptops such as the Acer Aspire V5-123 (£488.99).
Notebook PCs with a better processor family that might be worth considering include the Aspire ES1-111m (£193.00) (Intel Celeron), or the Aspire E3-112 (£139.99) (Intel Celeron) both from Acer which is also cheaper.