Need advice - first time marathon training

i'm hoping to do my first marathon at Fleetwood at the end of August - not very glamorous I know, but it's local

my usual regime is:

monday - 7km easy
tuesday - yoga
wednesday - 6km tempo
thursday - light cardio (usually cross trainer or 20km bike ride)
friday - 11k easy, or 6km tempo, or perhaps 5 * 800m intervals
saturday - rest or 30km bike ride
sunday - 21km easy minimum

my half marathon PB (so far) is 1:27:05, and my 10km PB is 39:09 - i'm aiming for sub-3:30 marathon PB if possible

stupid, i know, but i've ran the marathon distance in training before (last year) just as a test run - the next few days hurt a LOT but i seemed to cope well whilst on the run, and managed a time of around 3:37

i know i need to up my training for the proper marathon - i can possibly add another day of running into the program (perhaps tuesday) but upping the mileage of my weekly runs is difficult, primarily because i run on my work lunch-break during the week so time is an issue

i've tried to get up to 30 miles a week regularly (so ~50km) but i just can't seem to recover well enough in subsequent weeks, so the week after a 30 mile week i will usually only manage 20 miles - mainly due to niggles and aches and pains - primarily my inner shins seem to gripe the most

my shoes are correct for my gait, i eat well and correct, and i'm light and slim at 6ft 1in with 10.5 stone weight

can any of you seasoned marathon runners give me advice as to what i can fine tune with my routine in preparation for this first marathon? what do i need to do to recover quicker, and what can i do to help improve consistency?

thanks all - much appreciated

To be honest a 3:30 marathon is an absolute waste of time with someone with your PBs.  It's a joke - you should be looking at closer to 3 hours.  However, maybe you are taking into account the fact you aren't running anywhere near enough to do yourself justice in a marathon.  If you can't fix that I'd concentrate on shorter distances.

I see you are doing 2 quality workouts a week.  I suggest you give another shot at doing more mileage but making it all easy mileage.  Build up the mileage first, then add back in some quality sessions if you can. 

A simple reorganisation of your week to tue, thu, sat and sun will give you a second day of mileage unrestricted by work.  Why can't you run after work?

When you have failed at upping mileage in the past for how long did you try?

What have you tried for recovery?  There are lots of things you might try, proper nutrition within 45 minutes of completing your run, adequate sleep, post run stretching, icing, compression clothing, the stick, ice baths, self massage. 

Have you seen somebody about the problem with your shins? 

thanks for the help - it's much appreciated

i'm fairly certain i can fit in another session into my routine - especially if it's an easy session - tuesday is the better day as it mixes into my yoga (which is on a fixed day) and that *always* helps me both with recovery both for a tuesday run, and for the week (hence the tempo on wednesday), and also to loosen me up for the rest of the week.

shifting sessions, i've considered - the only thing that is putting me off your suggestion though is running 2 consecutive days on the weekend because i prefer to have a rest/cross train day on saturday so my legs are a bit more able for the sunday long easy session. i've recently found that doing my LSR on local trails is so much more relaxing (no cars etc) and definitely helps to lessen the impact on my lower legs that seems to be the bane of my training so far.

i can run after work - it's possible, as i haven't got a long commute. perhaps thursday with a revised schedule would be the better day?

my 30 mile+ regular routine usually lasted for perhaps 3 consecutive weeks - perhaps i need to do something along the lines of 2 alternating 30 mile weeks per month, and then build up over say 3 months to consecutive 30 mile weeks to give my body time to adapt?

recovery is usually along the lines of protein right after a run (can of tuna, mainly) or milk, with carbs (bagel, pasta etc), plenty of water then a stretching routine, and then later on ice possibly on my inner shins if they are griping me. i am making a concerted effort to lay off the drink on a weekend, as i find the less i have the more "prepared" my digestive system is for the rigours of a sunday LSR (bad experiences.....!). i'm trying to stay away from all this "recovery milk shake/powder/panacea of invulnerability" shite and go the natural route with my training diet.

not seen anyone about my shins, so far - perhaps i need to start making steps to get professional advice for the longer term. however they've definitely improved over the time of my (relatively short (2 years)) running career.

The alternating weeks sound like a good idea and don't be afraid to drop a quality session if that helps establish a better mileage base.  You can always add it back in.

Sounds like you're doing everything else right.