Thats nearly that same as mine, 248 and 307, is yours a standard car or modified? are you running the standard boost solenoid?

I have the following fitted to mine

Ford Tubular Manifold, Full Mongoose decat Exhaust, Samco Boost Hoses, Blitz SS DV, K&N GenII Induction Kit, MIL Eliminator, Pro Alloy chargecooler, Apexi boost controller.

I'm back at EA next wednesday having an uprated fuel pump fitted as the car was running lean higer up the reve range....

Where abouts in Kent are you??

Rgds, Bryan