Assured Tenancy

Possession - Section 8 and Section 21

Dear RLA, I spoke to Lisy yesterday about my query but I have some further questions please. Under ground 6 of a Section 8 I am aware that we can only give notice if we can prove that it would be impossible for the Tenants to remain whilst substantial works are carried out. In a run up to the new Electrical safety requirements deadline we need to rewire the whole property and, whilst on site, we need to fix some damp and roof issues, involving much replastering, redecorating, and new flooring. A modern kitchen and bathroom and new windows are all much needed. Our builder says it would be impossible for him to carry out these works with Tenants living there.If we obtained this in writing from the builder, would that be sufficient for us to explain to them that giving them notice is necessary and is a Court likely to back this up? If or not they agree are we are obliged to re-home them temporarily whilst works are carried out? Also are we obliged under the law to allow them back once works are complete. We would of course then apply for a rent review asking so a substantial rent uplift.