Office refit - inform landlord?

[warp9]

Hi. We currently rent a one floor office of around 6,000 sqft in an 'L' shape. It's fairly open plan with a couple of offices at each end.

Due to some internal changes we want to get rid of the offices at one end to create a complete open plan space and the other side create 5 new offices.

What are my obligations to inform the landlord and do I need to obtain any permissions from the council? Also, are there any health and safety requirements to meet?

Thanks in advance.

[warp9]

The only bit in our lease that I can find that refers to making changes states

'The Tenant shall not make any alteration to the Property without the consent of the Landlord, such consent not to be unreasonably withheld, and of the Superior Landlord in accordance with the terms of the Superior Lease.'

I guess the crux here is what constitutes an 'alteration to the property'. I have passed this on to my solicitor for review.

After meeting the contractor earlier, his response was that as what we are doing is temporary and classed as demountable walls, then the landlord not need know!

I'm more of the it's better to beg for forgiveness than ask for permission camp.