Time to move to dedicated hosting?

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We run a zen-cart store, and our traffic has been building steadily for the last year. Recently I have been doing speed tests on the site while while at times loading times are fine, other times it's very bad (the woes of being on a shared server). We want to have better/ consistent loading times.  We are currently on blacknights top tier shared hosting (30e per month i think). Blacknight support said that VPN wouldn't be much good to us (+ they are unmanaged) and they said we should look at a dedicated server, but they start at about 400e a month with blacknight. I have been getting a few quotes from other companies in the 170e-200e range for fully managed server + backups etc. There any other hosting providers anyone can recommend that offer fully managed dedicated servers on a budget range?
IMHO - You pay for services - hardware costs are probably the same for everyone. You'll appreciate the difference when you go down and need expert help in keeping you going. Not the time to save €200!
I have had a dedicated server(s) for past 10 years from a company in UK. Costs GB£130.00 per month, which includes full backup & restore solution. Overall am quite happy with the service. Having said that, I do mean to look at Irish providers, as I would prefer to try and keep business in Ireland. FYI, I have a number of OsCommerce sites running on the server.PM men if you want more info.