Quickest and most effective way to evict.

Tenancy Types and Management

You do not state when the tenancies end.
You ahve 2 options.
If you can get witness statements you can evict for nuisance using ground 14.
You can also evict using a s21 notice.
Both procedures are set out step by step on rla website.
Look in DOCUMENT CENTRE. First left hand column, first item entitled NEW POSSESSION AND SMALL CLAIMS PROCEDURES.
Please make sure you open every link
Dave A