Help comparing roof repair quotes

NewLandlord

Hi! I have quotes from three Checkatrade companies for repair work to the leaky roof of my 2 bedroom mid-terrace in Outer London.   However I am not technically well versed in roofing nomenclature so I am not sure of how different the work being offered is, or which quote is the best in terms of value for money.  Photos of the damage are linked and any feedback would be greatly appreciated.

Image links:
https://ibb.co/album/D4zHzR

The quotes are:

A - £2300   1 year guarantee
Supply And Fit New Torch On Felt To Parapet Walls Front,Back Of Property
Remove Ridges And Put Aside Then Reinstate Back Using A Dry Ridge System
Supply And Fit New Lead Replacement Flashing To Back Chimney
Supply And Fit A New Dry Valley To Replace Existing Zinc Valley
Supply And Fit New Tiles To Back Chimney And Valley
Use A 3-1 Mortar Mix To Re-flaunch Top Of Back Chimney Stack
Erect Scaffolding To Front Of Property


B - £2850  10 year guarantee
Remove all render and lead to flashing to party walls and chimney stacks.
Repair any badly damaged uncoverd brick work.
Install lead flashing to newly uncovered brick works to party walls of 25 meters, using 12inch  code 4 lead with correct upstands for water tight measure at 150mm with 20mm internal into brickworks.
Install render stop beads to meet lead flashings covering 75mm for water measures.
Apply render scratch coat to all uncovered brick works to party walls using a 3-1 mix ratio of plastering sand and cement leaving to dry for 24hr.
Apply render finish coat to newly applied scratch coat using a 3-1 mix ratio of plastering sand and cement.
Remove badly installed valley tiles and valley liner.
Install new zinc valley liner.
Install new valley cut tiles correctly with a 100mm center valley for rain fall to run freely to guttering.
Remove all loose ridge tiles and mortar.
Rebed ridge tiles using a 3-1 mix ratio of building sand and cement.
Remove all debris and waste from site.


C - £ 4900
To supply scaffolding access to front and rear of property.
On inspection of roof, roof is covered with Redland 49’s and felt underlay. Ridge tiles appear to have sagged and mortar has perished. Felt lining has crumbled and broken away, fallen down at adjoining walls. Chimney stack to back addition has been removed and possible water coming through remainder of chimney stack.
To remove ridge tiles and roof tiles, put aside for reuse.
Hack off rendering to parapet walls and around chimneys.
To remove felt and baton de nail rafters.
To supply and fix additional Rockwall insulation to loft area and back addition to help prevent condensation.
To re felt roof using breathable membrane and baton roof using tanilised treated timber, fixed at correct gauge for tiles nailed to rafters.
To re fix tiles, nailed accordingly, supply additional tiles as necessary and allow for 2 vented tiles per side.
To chase walls, supply and fix 9 inch lead flashings tucked and wedged dressed down over roof tiles and allow for new back gutters behind chimneys in lead.
To fix render beads and re render above flashings applying 2 coats of sand and cement floated up smoothly.
To fix ridges using dry ridge system, ridge tile bedded at both ends securely screwed down.
To check all gutters and down pipes, clean out debris and replace, repair as necessary.
To clear site of all debris.


Thanks for looking!

tacpot12

Quote 3 is proposing to remove all the existing tiles across the whole roof, repair the damage, and reinstall the existing tiles. It is proposing a much more comprehensive process than either quotes 1 or 2, and it is proposing a dry system for fixing the ridge. Quote 2 is proposing a wet system for fixing the ridge, which is no longer regarded as best practice. Quote 3 is less clear about how the valley is going to be reinstated, but my reading is that it will be done in lead, not zinc. 
Quote 1 doesn't look as though it is addressing all the problems that you have.  

However, from your photos it is not clear that the main part of the roof actually needs removing and re-laying, but it is the best way to fix the problems (providing the roofer is any good). You should try to talk to a previous customer of the firm you want to use just in case they have left someone else with problems.  

NewLandlord

Thanks for the feedback - as a neophyte in these matters a response  by someone who is familiar with the terminology is greatly appreciated.  I have a couple of follow up questions:

1)
From my quick Google search it seems that whether a valley is made using zinc or lead doesn't seem to matter to much as both will outlast the rest of the roof anyway .  Is this correct?

2)
I assumed from the price that Quote 1 was far more comprehensive and it is good to know that it was.   However, I have heard that a new roof might only cost around £6K for a property like mine (typical 2 bedroom terraced in Outer London).   Or is that basically what he is suggesting?

3)  

Quote 2 is offering a 10 year guarantee  (whereas quote 1 only offers a one year guarantee).   Even though dry ridges are the encourage option now apparently, is the work still likely to hold for 10 years?   I understand new roofs have a 25 year guarantee so spending 3K rather than 6K now and if the work is expected to last over 10 years anyway seems a decent choice.   Is this a reasonable thing to do?

Thanks to anyone who actually reads this all .