So you cant offset the entry into these chambers. I can see why older systems would be a problem but surely new development areas could be looked at.                                                                                                                                                                             

Offset entries!  I'm impressed.

You can offset the entries to chambers, but it is only worth doing under certain circumstances.  For starters you need a man sized chamber under the manhole anyway and then you need an underground crawler passage from there to the main chamber.

As such the amount of space you save under the manhole isn't that much but the increased cost is pretty substantial.

Offset entries therefore are generally only provided when development work dictates a new/amended highway layout and the cost of relocating an existing chamber is prohibitive.

As such in my twenty odd years in the business, I've only ever designed one offset chamber.  This was for a scheme in Grimsby where we discovered that an eighteen duct fibre optic BT route that was providing feeds from and to the rest of the uk, was about 250mm below the footway instead of about a metre as would be normal for a route of this magnitude.  Under the carriageway we also found these ducts fed into a BT chamber that BT didn't know about despite it being about the size of a small garage and there wasn't enough room on the new island due to go above it for the manhole!!

Relocating these would have cost my client about an extra £1.2m on a scheme that was estimated to only cost about £550k but I managed to convince BT to allow them to remain where they were and to build an offset entry into the existing chamber.

I'm still waiting for a thank you from my client!                                                                                                                                                                              

and..   same goes for rural roads run yhem in the fields Im sure the cows or crops wont mind   While the cows may not mind, the farmer certainly would, when his plough gets stopped dead in its tracks by one (Ploughing round obstacles is a major pain in the backside)